Urine Sediment Photographs

Transcription

1 CMP-17 Urine Sediment Photographs Case History CMP-17 This urine sample is from a patient whose chief complaint is vaginal itching. Laboratory data include: specific gravity = 1.015; ph = 6.0; blood, leukocyte esterase = positive; glucose, ketones, protein, nitrite = negative. Identify the arrowed object(s) in each image. CMP Participants Performance Yeast/fungi, extracellular Good The arrowed object is yeast/fungi as correctly identified by 99.9% of participants. The most common yeast in urine is Candida albicans. Candida albicans appears as colorless, ovoid shaped, thick walled cells (5 to 7 µm) that may demonstrate bud formation. In addition, Candida species can form elongated cells, referred to as pseudohyphae that can be up to 50µm in length. 60

2 CMP-18 Urine Sediment Photographs Case History CMP-18 This urine sample is from a 1-year-old patient with diarrhea, fussiness, and poor eating for the past week. Laboratory data include: specific gravity = 1.030; ph = 5.0; ketones, glucose, leukocyte esterase = positive; protein, nitrite = negative. Identify the arrowed object(s) in each image. CMP Participants Performance Uric acid Good The arrowed objects are uric acid crystal as correctly identified by 97.3% of participants. Uric acid crystals are yellow to brown in color, strongly birefringent, vary in size and shape, and are formed in acid urine. Common forms are four sided, flat, and whetstone. They may appear as six sided plates, needles, lemon-shaped, spears, clubs, wedge shapes, stars, or other odd shaped crystals. The arrowed uric acid crystals in this case have a rhomboid shape. Massive numbers of uric acid crystals are seen in uric acid nephropathy and tumor lysis syndrome. 61

3 CMP-19 Urine Sediment Photographs Case History CMP-19 This urine sample is from a 1-year-old patient with diarrhea, fussiness, and poor eating for the past week. Laboratory data include: specific gravity = 1.030; ph = 5.0; ketones, glucose, leukocyte esterase = positive; protein, nitrite = negative. Identify the arrowed object(s) in each image. CMP Participants Performance Mucus strands Good The arrowed objects are mucus strands as correctly identified by 99.1% of participants. Mucus: strands or threads appear as translucent, delicate long wavy intertwined aggregates. Mucous strands do not polarize light (to distinguish them from fiber) but they are more obvious with phase microscopy. Mucus arises from the glands in the lower urinary tract or vagina. 62

4 CMP-20 Urine Sediment Photographs Case History CMP-20 This urine sample is from a 1-year-old patient with diarrhea, fussiness, and poor eating for the past week. Laboratory data include: specific gravity = 1.030; ph = 5.0; ketones, glucose, leukocyte esterase = positive; protein, nitrite = negative. Identify the arrowed object(s) in each image. CMP Participants Performance Leukocyte (neutrophil, eosinophil, lymphocyte) Good The arrowed object is a leukocyte as correctly identified by 98.9% of participants. Unstained leukocytes (WBCs) in urine can include neutrophils, lymphocytes, eosinophils, as well as monocytes/macrophages. Small number of neutrophils (<5/HPF) may be seen in normal urine sediment. Neutrophils in freshly voided urine appear as colorless granular cells about 12um in diameter (double the size of RBC). The nuclear detail is well defined, and fills most of the cytoplasm. In hypotonic urine, neutrophils swell and may contain visible cytoplasmic granules with Brownian movements. These neutrophils with refractile dancing granules are called glitter cells. Neutrophils are phagocytic and are often seen with pseudopods. Increased number of neutrophils and/or the presence of clumps of leukocytes in urine suggests acute infection. Neutrophils in urine may also be derived from secretions the male or female genital tract. Lymphocytes: are rarely present in urine. They appear as round cells that are slightly larger than RBC with high N/C ratio. Lymphocytes may be seen in urine during the first few weeks after renal transplant rejection. Eosinophils appear as round or oval cells, which are slightly larger than neutrophils. Increased numbers of eosinophils are found in patients with interstitial nephritis. George Girgis, MT Hematology and Clinical Microscopy Resource Committee 63

5 CMP-21 Body Fluid Photographs Case History CMP-21 The patient is a 60-year-old male with a history of lymphoma who developed a cerebral hemorrhage. Cerebrospinal fluid laboratory findings include: WBC = 98/µL (0.098 x 10 3 /µl); RBC = 291/µL (0.291 x 10 3 /µl). Identify the arrowed object(s) in each image. CMP Participants Performance Erythrocyte, mature Good The arrowed cell is a normal erythrocyte as correctly identified by 99.8% of participants. An erythrocyte is a mature, non-nucleated red cell of fairly uniform size (6.7 to 7.8 microns in diameter) and shape biconcave disc appearing as round or slightly ovoid on a smear. It contains hemoglobin and stains red-pink. A zone of central pallor due to the biconcavity of the cell occupies approximately one-third (2-3 microns) of the cell diameter. 64

6 CMP-22 Body Fluid Photographs Case History CMP-22 The patient is a 60-year-old male with a history of lymphoma who developed a cerebral hemorrhage. Cerebrospinal fluid laboratory findings include: WBC = 98/µL (0.098 x 10 3 /µl); RBC = 291/µL (0.291 x 10 3 /µl). Identify the arrowed object(s) in each image. CMP Participants Performance Mitotic figure Good The arrowed cells is a mitotic figure as correctly identified by 97.1% of participants. A cell containing a mitotic figure varies in size; it may or may not be larger than the surrounding cells. The cytoplasm has color and granulation characteristic of the resting cell. When the cell undergoes mitosis, typical nuclear features are no longer present. They may take varying shapes including a daisy-like form or a mass with irregular projections. The irregular projections represent individual chromosomes as seen in this example. 65

7 CMP-23 Body Fluid Photographs Case History CMP-23 The patient is a 60-year-old male with a history of lymphoma who developed a cerebral hemorrhage. Cerebrospinal fluid laboratory findings include: WBC = 98/µL (0.098 x 10 3 /µl); RBC = 291/µL (0.291 x 10 3 /µl). Identify the arrowed object(s) in each image. CMP Participants Performance Lymphoma cell Blast Malignant Cell Immature/Abnormal cell, Referee Educational Educational Educational Educational The arrowed cell is a lymphoma cell as correctly identified by 57.9% of participants. Lymphoma cells can exhibit a variety of appearances depending on the subtype of the underlying tumor. Definitive diagnosis can be difficult. Cells can exhibit a variety of sizes, shapes, nuclear and cytoplasmic characteristics. While lymphoma cells are usually round to oval, they can be irregular. Cell size ranges from 8 to 30 microns and the N:C ratio varies 7:1 to 3.1. It is critical to obtain accurate clinical history. Knowledge of a previous diagnosis of lymphoma greatly aids in the identification of these cells. 66

8 Discussion: CMP-B Body Fluid CM Cerebral spinal fluid bathes the brain and spinal cord. The cerebral spinal fluid (CSF) is produced primarily (70%) from secretions in the four ventricles of the brain by the highly vascular choroid plexus (vascular finger-like folds in the pia mater). The ependymal cells that line the brain and spinal cord also play a minimal role in the production of cerebral spinal fluid. The formation of CSF is a selective secretion from plasma, not an ultrafiltrate. This is explained by high CSF concentrations of some solutes (Na, Cl, Mg) and lower CSF changes of others (K, total calcium) compared with plasma. If simple ultrafiltration were responsible for CSF production these solute differences would not exist. CSF flows in spaces between the arachnoid and pia mater. From its formation in ventricles CSF circulates to the brainstem and spinal cord primarily through pressure changes caused by postural, respiratory and circulatory pressures, which eventually flow in the subarachnoid space to the outer surface of the brain and is reabsorbed in the blood via one way valve in the arachnoid villi. CSF formation, circulation and reabsorption into blood make up a dynamic process that constantly turns over about 20 milliliters per hour. If the flow between the production and reabsorption into blood is disrupted for any reason, CSF will accumulate, producing hydrocephalus. The total volume of CSF in an adult ranges from milliliters, whereas the volume in neonates is significantly smaller ranging from milliliters. The capillary endothelium in contact with the CSF enables the transfer of substances from the blood into CSF and vice versa. This capillary endothelium differs from the endothelium in other tissues by the presence of tight junctions between adjacent endothelial cells. These tight junctions significantly decrease the extracellular passage of substances from the blood plasma into the CSF. This interface between the blood and CSF is called the blood brain barrier and it accounts for the observed changes of electrolytes, protein and other solutes. An example of the selectivity and effectiveness of the blood brain barrier is a failure of some antibiotics, given intravenously, to enter the cerebral spinal fluid, although these antibiotics freely penetrate all the tissues of the body. Oftentimes chemotherapy is given directly into the spinal canal so that the problem of crossing the blood brain barrier is averted and an occult malignancy can be treated. Case Summary: This case is a 60-year-old with history of lymphoma who developed a cerebellar hemorrhage. CSF WBC 98/µL and RBC 291/µl. The large number of white cells and red blood cells is abnormal as generally 4-5 white cells are expected in a normal adult and no red blood cell are expected unless there is a traumatic puncture. Laboratory tests on CSF are based on the clinical scenario and often include cell count, protein and glucose levels, cytology, and microbiology studies. Other tests which may be useful include albumin and IgG levels to evaluate the blood brain barrier, protein levels to evaluate for oligoclonal bands which may be observed in multiple sclerosis and other neurologic diseases. Lymphomas can involve the central nervous system (CNS) either as the sole area of disease (primary CNS lymphoma) or a secondary spread of systemic disease. Secondary involvement of the CNS by lymphoma occurs in many ways and rapid control is necessary. Lymphoma cells are thought to enter the central nervous system by hematogenous spread, direct extension from adjacent bone metastases or by growth along neurovascular bundles. Most episodes of central nervous system lymphoma are non-hodgkin lymphomas and occur in the setting of relapsed disease. However, a significant percentage may have had subclinical CNS involvement at the time of diagnosis. This is suggested by the high rate of CNS involvement within six months of patients presenting with aggressive lymphomas. The type of lymphoma represented in this case is that of a large cell lymphoma. This type exhibits some of the most abnormal morphology with very large cells (20-30 microns) with scant to moderate amounts of basophilic cytoplasm. The nuclei are generally round to oval but may be angulated, folded, indentured or convoluted. 67

9 Nucleoli are prominent and may be single or multiple. Other types of lymphomas and malignancies may be found in CSF. Immunophenotyping, cytogenetic and molecular studies may be needed to determine the type of lymphoma. Table 1 Malignant neoplasms in cerebrospinal fluid Hematopoietic Acute lymphoblastic leukemia Acute myelogenous leukemia Chronic leukemias Non-Hodgkin lymphoma Hodgkin lymphoma Metastatic or direct extension. Carcinoma. Malignant melanoma. Sarcoma. Unknown primary site Germ cell tumors Primary central nervous system lymphoma Other primary central nervous system neoplasms Dr. Alice Werner, MD Hematology and Clinical Microscopy Resource Committee 68

10 CMP-24 Body Fluid Photographs Case History CMP-24 The patient is an 86-year-old female with a history of breast cancer presenting with shortness of breath. Pleural fluid sample laboratory findings include: WBC = 913/µL (0.913 x 10 3 /µl); RBC = 735/µL (0.735 x 10 3 /µl). Identify the arrowed object(s) in each image. CMP Participants Performance Lymphocyte Good The arrowed cell is a lymphocyte, as correctly identified by 97.2% of participants. The normal small mature lymphocyte measures from 7 to 9 μm. The chromatin is diffusely dense with little parachromatin and no apparent nucleolus. The N:C ratio is high and a rim of blue agranular cytoplasm is present. The cytoplasmic projections are likely an artifact due to cytocentrifugation, as is the nuclear fold in the adjacent large reactive lymphocyte. Small nucleoli are more commonly seen in effusions than in the peripheral blood. Martha R. Clarke, MD Hematology and Clinical Microscopy Resource Committee 69

11 CMP-25 Body Fluid Photographs Case History CMP-25 The patient is an 86-year-old female with a history of breast cancer presenting with shortness of breath. Pleural fluid sample laboratory findings include: WBC = 913/µL (0.913 x 10 3 /µl); RBC = 735/µL (0.735 x 10 3 /µl). Identify the arrowed object(s) in each image. CMP Participants Performance Malignant cell (nonhematopoietic) Mesothelial Cell Immature/Abnormal Cell, Referee Lymphocyte, Reactive Educational Educational Educational Educational The arrowed cells are non-hematopoietic malignant cells, as correctly identified by 73.4 % of participants. Nonhematopoietic malignant cells form cohesive clusters, in contrast to lymphocytes. The cells are very large compared to the adjacent small lymphocytes. The nuclear to cytoplasmic ratio is high compared to monocyte/macrophages and the nuclei contain large nucleoli. Morphology on a cell block and immunohistochemical stains are useful in confirming the epithelial nature of the cells and the likely primary source, which is breast carcinoma in this case. 70

12 CMP-26 Body Fluid Photographs Case History CMP-26 The patient is an 86-year-old female with a history of breast cancer presenting with shortness of breath. Pleural fluid sample laboratory findings include: WBC = 913/µL (0.913 x 10 3 /µl); RBC = 735/µL (0.735 x 10 3 /µl). Identify the arrowed object(s) in each image. Referees CMP Participants Performance Identification No. % No. % Evaluation Macrophage containing abundant small Acceptable lipid vacuoles/droplets (Lipophage) Monocyte/macrophage Good The arrowed cell is a monocyte/macrophage, as correctly identified by 44.8% of participants. An acceptable answer is also that of a macrophage containing abundant small lipid vacuoles/droplets (lipophage). In fluids, monocytes are usually 12 to 20 µm while macrophages vary in size from 15 to 80 μm. Monocyte/macrophage morphology in fluids is quite variable with a continuum ranging from features of a typical peripheral blood monocyte to a vacuolated, activated stage with morphology of a typical macrophage. The nucleus of a macrophage may have various round, oval, lobular or bean shapes, and the cytoplasm is usually pale bluegrey. Vacuolated macrophages with round nuclei may appear very similar to vacuolated mesothelial cells. Typical lipid- containing macrophages have variable large and small vacuoles in the cytoplasm. In contrast, lipophages contain small, very uniform cytoplasmic vacuoles. Lipophages in pleural and pericardial fluids contain phagocytized lipids derived from cell membrane destruction. They may be seen effusions due to many causes, both benign and malignant. Alice L. Werner, MD Hematology and Clinical Microscopy Resource Committee 71

13 Breast Cancer (adenocarcinoma) in Pleural Fluid The patient is an 86-year-old female with a history of breast cancer presenting with shortness of breath. Pleural fluid sample laboratory findings include: WBC = 913/µL (0.913 x 10 3 /µl); RBC = 735/µL (0.735 x 10 3 /µl). Identify the arrowed image(s). (PLEURAL FLUID, CYTOCENTRIFUGE, WRIGHT-GIEMSA) Case Discussion This case is an example of metastatic breast carcinoma in the pleura with resulting pleural effusion and secondary respiratory compromise. Breast cancer is the second most common cause of malignant pleural effusion, following lung cancer in frequency. Other malignancies causing malignant pleural effusion include adenocarcinoma of unknown primary, lymphoma and leukemia, and tumors of the gastrointestinal tract and ovary. Approximately 50% of patients with metastatic lung and breast cancer will develop pleural effusions. The majority of the pleural effusions in these patients occur on the same side as the primary tumor. The pleura is a double-layered membrane composed of visceral pleura covering the lung and the parietal pleura covering the chest wall. These two layers are normally separated by a small amount of fluid which is produced by the parietal pleura and absorbed by the visceral pleura. The hydrostatic pressure in capillaries, plasma oncotic pressure (a result of plasma proteins) and permeability of capillaries determines the rate of fluid production. Resorption of fluid is via the lymphatic vessels and venules of the pleura. Injury or disease states that disrupt this balance of fluid movement across the membranes may result in an effusion either through increased fluid production, decreased resorption or a combination. Increased hydrostatic pressure as seen in congestive heart failure will usually result in bilateral effusions with few cellular elements (transudate). Infections including bacterial pneumonia cause increased capillary permeability resulting in effusions with leukocytes and protein (exudates). Multiple factors may be involved in pleural effusions in malignant neoplasms. Lymphatic and capillary obstruction by the neoplastic cells in the pleural tissues will result in decreased absorption of fluid and protein. Cytokines produced by tumor cells may cause increased capillary permeability and increased fluid production. Additionally, cancer patients who are malnourished and have decreased plasma proteins (hypoproteinemia) may develop pleural effusions due to decreased oncotic pressure in the absence of tumor in the pleura. Classification of pleural effusions and causes based upon this is shown in Table 1. Table 1. Pleural Fluid Classification and Causes Transudates Due to Increased Hydrostatic Pressure Congestive Heart Failure Cirrhosis with Ascites Due to Decreased Plasma Oncotic Pressure Nephrotic Syndrome with Hypoproteinemia Malnutrition Exudates Due to Increased Capillary Permeability or Decreased Lymphatic Resorption Infection, Bacterial or Fungal Metastatic carcinoma, lymphoma, primary tumors of the lung and Mesothelioma of the pleura Collagen vascular disorders including, Rheumatoid Arthritis, Systemic Lupus erythematosus Pulmonary infarction Malignancy is one of the most frequent causes of pleural effusion, followed by infections, congestive heart failure, unknown causes, pulmonary embolism and infarction and cirrhosis. Thoracentesis (removal of pleural fluid) is important, not only for therapeutic purposes of relieving pressure on the adjacent lung, but also for diagnosis. Microscopic and cytologic evaluation of the pleural fluid is invaluable in diagnosing malignant pleural effusions and samples suspected of harboring malignancy of unknown etiology should be sent to cytology for evaluation, in addition to performing chemistry testing and cell counts. 72

14 Routine laboratory tests include gross examination of the fluid and determination of the pleural fluid protein and lactate dehydrogenase (LDH). Using the Light criteria, the effusion is considered an exudate when it meets one or more of the following criteria: Pleural fluid/serum protein ratio >0.50 Pleural fluid/serum LDH ratio >0.60 Pleural fluid LDH >2/3 upper limit of normal serum LD Leukocyte counts may be performed manually using a hemocytometer or on automated instruments. Leukocyte counts <1000/µL are suggestive of a transudate and >1000µL, an exudate; however, these counts are limited in their ability to distinguish the two, as there is a good deal of overlap. Red blood cell counts >100,000/µL are suggestive of malignancy, trauma or pulmonary infarction, but are not specific. Differential leukocyte count may be performed on an air-dried Wright-stained cytocentrifugation slide, filtration preparation or automated concentration method with Papanicolaou stain, or by automated cell count. A fluid with a predominance of neutrophils is observed in inflammatory conditions, including bacterial pneumonia. Lymphocyte predominant pleural fluid cell counts occur in tuberculosis, viral infections, malignancy, and collagen vascular disorders. Eosinophilia is seen in pneumothorax, trauma, pulmonary infarction, parasitic and fungal infections and drug reactions. The hematology laboratory has been shown to be very effective in identifying malignant cells in fluids, especially hematologic malignancies. When malignant cells are suspected, the fluid should be evaluated by cytologic methods, as well, which will increase the sensitivity. Malignant cells in effusions tend to stand out as a discrete extra or foreign population of cells. The malignant cells are generally very large with high N: C ratios, irregular nuclear membranes, prominent nucleoli and atypical mitotic figures. The tumor cells may form large clusters and three dimensional aggregates with ill-defined cell borders. This contrasts with mesothelial cells which do not show an increased N:C ratio and maintain smooth nuclear membranes, small nucleoli and borders between cells in clusters with clear spaces or windows between cells. The presence of cytoplasmic mucin in adenocarcinoma, keratin in squamous cell carcinoma or melanin in melanoma identifies these cells as abnormal. In some malignancies with medium-sized cells the tumor cells may closely resemble mesothelial cells or histiocytes, and it is difficult to identify them as a second or abnormal population of cells. This may be seen in low-grade serous ovarian carcinoma and lobular breast carcinoma. Marked reactive changes may occur in mesothelial cells with tumor infiltration, mimicking cancer cells, further adding to the diagnostic difficulty. Cytologic evaluation of body fluids increases sensitivity for detection of tumor and also allows for further characterization of cells of interest. In addition to cytospin preparations, cell blocks are usually prepared by embedding a pellet of cells in paraffin, allowing for pathologic evaluation and staining similar to tissue excision or biopsy. Immunohistochemical stains on cell block preparations are extremely useful in further classifying the atypical cells in effusions.immunostains that preferentially stain mesothelial cells, such as HBME-1, calretinin, and D2-40 and those that stain adenocarcinoma, such MOC-31, B72.3, CEA, are useful in separating reactive mesothelial cells from metastatic adenocarcinoma. More specific immunostains can further classify metastatic tumor cells as to the primary site of origin. Correlation with the clinical and radiographic findings is essential. References. Kjeldsberg CR and Knight JA. Body Fluids, 3rd ed. Chicago, IL: American Society of Clinical Pathologists; McPherson RA and Pincus MR. Eds. Elsevier. Henry s Clinical Diagnosis and Management by Laboratory Methods, 22 nd ed. Philadelphia, PA: DeMay R, The Art and Science of Cytopathology, 2 nd ed. Chicago, IL: American Society for Clinical Pathology: Dr. Martha R. Clarke, MD Hematology and Clinical Microscopy Resource Committee 73

15 CMMP-36 Clinical Microscopy Miscellaneous Photographs CMMP Participants Performance Ferning present Good This vaginal pool sample exhibits ferning. The fern test, in conjunction with the Nitrazine test, is highly sensitive and specific for the detection of ruptured membranes and the early onset of labor. The fern test is performed by collecting a vaginal pool sample and allowed the fluid to air dry on a microscopic slide for 5-7 minutes. The slide is examined using a microscope to detect ferning, an elaborate arborized crystallization pattern. The test may be positive as early as 12 weeks of gestation. Inadvertent contamination of the specimen by cervical mucus may cause a falsely positive result but the arborization pattern is less elaborate and normally will not form after the first trimester of pregnancy due to high levels of progesterone present. 74

16 CMMP-37 Clinical Microscopy Miscellaneous Photographs CMMP Participants Performance Yeast/Fungi absent Good This KOH preparation does not exhibit any yeast or pseudohyphae. The large object appears to be amorphous debris. Vulvovaginal candidiasis is a common fungal infection that occurs where there is overgrowth of Candida species. While small numbers of Candida are normally present, changes in vaginal fluid acidity or hormonal changes may be responsible for symptomatic Candida infections. 75

17 CMMP-38 Clinical Microscopy Miscellaneous Photographs CMMP Participants Performance Eosinophils absent Good This nasal smear is negative for eosinophils. The photomigrograph contains only superficial epithelial cells with overlying bacteria. Nasal eosinophils are seen in patients with clinical allergic rhinitis. In nonallergic causes of nasal discharge, either acellular mucus or neutrophils will be present on the nasal smear. Nasal smears for eosinophils are prepared by having the patient blow his/her nose in a nonabsorbent material (wax paper, plastic wrap). A swab is then used to transfer the mucus to a glass slide. A thin smear is prepared and let air dry. Staining may be performed using a Wright-Giemsa stain or a Hansel stain. The advantage to the Hansel stain is that the eosinophils stain bright red, whereas with a Wright-Giemsa stain the eosinophil granules may take on a more bluish appearance. 76

18 CMMP-39 Clinical Microscopy Miscellaneous Photographs CMMP Participants Performance Pinworm present Good This unstained pinworm prep exhibits the presence of a pinworm egg just off center. The nematode (roundworm) Enterobius vermicular is (previously Oxyuris vermicular is) also called human pinworm. (Adult females: 8 to 13 mm, adult male: 2 to 5 mm.) Humans are considered to be the only hosts of E. vermicularis. A second species, Enterobius gregorii, has been described and reported from Europe, Africa, and Asia. For all practical purposes, the morphology, life cycle, clinical presentation, and treatment of E. gregorii is identical to E. vermicularis. 77

19 CMMP-40 Clinical Microscopy Miscellaneous Photographs CMMP Participants Performance Leukocytes present Good This Wright-Giemsa stained stool specimen exhibits neutrophils, some which exhibit degeneration. Leukocytes may be detected in stool smears from patients with enteric pathogens, although this test is considered neither very specific nor sensitive for the detection of enteric pathogens. Fecal leukocytes are more likely to be detected in patients infected with Shigella, Salmonella or Campylobacter organisms. If the patient is suspected of having an enteric pathogen, a stool culture should be performed. 78

20 CMMP-41 Clinical Microscopy Miscellaneous Photographs Referees CMMP Participants Performance Identification No. % No. % Evaluation Trichomonas present Good Sperm absent Good Clue cells absent Good Epithelial cells absent Good Epithelial cells present Unacceptable This is an unstained vaginal specimen exhibiting Trichomonas. The organism in this preparation is a Trichomonas and can be identified by its characteristic flagella. The organism can be identified by its pear shape, flagella and eccentrically placed nucleus. Trichomonas has 4 anteriorly directed flagella and one posteriorly. Trichomonas vaginalis is a microscopic parasite found worldwide. Trichomoniasis is one of the most common sexually transmitted diseases, mainly affecting sexually active women. In North America, it is estimated that more than 8 million new cases are reported yearly. Trichomoniasis is spread through sexual activity. Infection is more common in women who have had multiple sexual partners. The normal incubation period is 4-28 days. The onset of symptoms such as vaginal or vulval pruritus and discharge is often sudden and occurs during or after menstruation as a result of the increased vaginal acidity. The diagnosis of this infection in children may indicate the following: Infants: If an infant is infected, it is possible that the mother spread infection during childbirth. The mother should be checked for infection. Young children: Because trichomoniasis is an STD, infection in a young child may indicate sexual abuse. If sexual abuse is suspected, an evaluation for other STDs is recommended. Teenagers: Because trichomoniasis is an STD, infection in a teenager may indicate sexual activity or sexual abuse. An evaluation for other STDs is recommended. Sperm are absent in this specimen and clue cells are also absent. Epithelial cells are absent as correctly identified by 80% of referees and 76.5% of participants. Squamous cells from skin may be found in fluids As a contaminant. Squamous epithelial cells are large (30 to 50 µm), round to polyhedral shaped cells with a low nuclear to cytoplamic ration (1:1 to 1:5). The nucleus is round to slightly irregular, with a dense, pyknotic chromatin pattern and no visible nucleoli. Trichomonas trophozoites range in size from 7 to 23 µm, with an average of 13 µm. Squamous epithelial cells are much larger and generally have a centrally located nucleus. Alice L. Werner, MD Hematology and Clinical Microscopy Resource Committee 79