Disorders of Cell Growth & Neoplasia. Histopathology Lab

Transcription

1 Disorders of Cell Growth & Neoplasia Histopathology Lab Paul Hanna April 2010

2 Case #84 Clinical History: 5 yr-old, West Highland White terrier. skin mass from axillary region. has been present for the last 10 months with no apparent change in size.

3 Cutaneous hemangioma, dog. Note well delineated, diffuse red mass in skin / subcutis.

4 The mass appears well demarcated

5 Note, the mass is well demarcated from the adjacent normal tissue

6 Note, mass is composed of variable sized spaces / channels filled with blood

7 Note, mass is composed of variable sized spaces / channels filled with blood

8 Note, blood filled spaces are separated by usually small amounts of fibrous stroma.

9 Note, blood filled spaces lined by relatively uniform endothelial cells

10 Case #84 Description: on low-power exam, the mass is well circumscribed and extends from the deep dermis of the overlying skin into the underlying subcutis with at least narrow zones of normal tissue at the peripheral margins. at higher magnification, it consists of variable sized, endothelial lined spaces / channels which are separated by usually small amounts of fibrous stroma. the nuclei of the lining endothelial cells are elongate with dense chromatin, usually inapparent nucleoli, mild anisokaryosis and no apparent mitotic figures. Morphologic Diagnosis: Cutaneous hemangioma Comment: a relatively common benign neoplasm of the dermis / subcutis of dogs (note: hemangiosarcomas not common in skin, but more common in spleen, heart). usually solitary, but occasionally can occur at multiple sites. some cutaneous hemangiomas are associated with prolonged exposure to sunlight.

11

12 Case #219 Clinical History: 8 yr-old, spayed-female, Shetland sheepdog. dog presented initially for impacted colon; enemas relieved impaction, but dog still had problems defecating. physical exam revealed stricture at colo-rectal junction. affected area was surgically resected. local lymph nodes are enlarged and 1-2 mm diameter masses are scattered throughout the omentum. main differential diagnoses are fibrous stricture (post inflammatory) or adenocarcinoma.

13 Grossly, an intestinal adenocarcinoma in the early stages, will show ulceration with variable thickening of the bowel wall (arrows)

14 In the latter stages of tumor development it becomes more obviously a neoplastic process by gross examination alone.

15 Normal segment / normal thickness of colon Thickened region of colonic wall

16 Relatively normal segment of colon wall

17 Note altered appearance of mucosa from the more normal area to the right. Note extensive invasion of the altered colonic glands into the underlying submucosa

18 Note invasion of the altered glands extends beyond submucosa into the underlying muscle layers

19 Note altered appearance of mucosa from the more normal area to the right.

20 Note irregular shape and crowding of epithelium in the altered invading glands

21 Note irregular shape and crowding of epithelium in the altered invading glands

22 Note features of anaplasia including pleomorphism and increased numbers of mitotic figures can be appreciated at higher magnifications

23 Features of anaplasia including pleomorphism, large nuclei with multiple nucleoli and increased numbers of mitotic figures can be seen at higher magnification.

24 Case #219 Description: on low-power exam, there is locally extensive thickening of the intestinal wall. at higher magnification the intestinal wall thickening is due to transmural infiltration by neoplastic epithelial tissue. in many areas this neoplastic epithelium forms glandular structures (note anaplasia); many of which are dilated (cystic) and contain mucus and/or cellular debris. latter structures are surrounded by fibrosis & variable numbers of inflammatory cells. Morphologic Diagnosis: Intestinal (colonic) adenocarcinoma Comment: this neoplasm showed extensive local invasion of the intestinal wall (it had also metastasized to local lymph nodes). some studies suggest that 50% of intestinal adenocarcinomas have metastasized by the time of recognition of the primary neoplasm. the most common metastatic sites are to the drainage lymph nodes and the liver.

25

26 Case #220 Clinical History: 7 yr-old, spayed-female, DSH, cat. mass removed from left cranial mammary gland also submitted regional lymph node.

27 Mammary tumors, gross, with cut surface (right)

28 Regional lymph node Highly cellular mass in mammary region Adjacent skin / subcutis

29 This neoplasm shows areas of local invasion into adjacent skin.

30 Areas of local invasion into adjacent skin Irregular shaped and variable sized glands with crowded epithelium

31 At higher magnification features of anaplasia including pleomorphism (mild to moderate) and increased numbers of mitotic figures can be seen.

32 Lymph Node Arrows roughly show the extent of the effacement of the lymph node by the tumor metastasis.

33 Relatively normal cortical region of node with lymphoid follicle. Area of lymph node effaced by neoplastic tissue

34 Higher magnification showing neoplasm invading / effacing cortical region of lymph node

35 At higher magnification features of anaplasia including pleomorphism (mild to moderate) and increased numbers of mitotic figures can be seen in the neoplastic epithelial cells.

36 Case #220 Description: on low-power exam, a section of mammary gland has a poorly delineated mass extending from the skin surface into the underlying tissue and a small lymph node is partially effaced by a similar mass. at higher magnification the masses are seen to consist of cords and glandular structures (tubules and acini with some papillary structures) composed of neoplastic epithelium within a fibrous connective tissue stroma. the neoplastic cells show moderate pleomorphism, loss of polarity and numerous mitotic figures. Morphologic Diagnosis: Mammary gland adenocarcinoma with lymph node metastasis Comment: from a statistically point of view mammary tumors in cats are mostly malignant (~ 9:1 ratio of malignant to benign) while the reverse is true of dogs. the local invasion and cellular anaplasia of the primary tumor in this case is highly suggestive of a malignant biologic behavior; however the additional feature of metastasis to the local lymph node is an unequivocal indicator of malignancy.

37