Intra-abdominal desmoplastic small round cell tumor: CT findings and clinicopathological correlation in 3 cases

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1 Intra-abdominal desmoplastic small round cell tumor: CT findings and clinicopathological correlation in 3 cases Dr. Eiriz, Sergio Dr. Eiriz, Conceiçao Sergioe Silva, Joao Paulo Dr. Radiology Conceiçao Departament e Silva, Joao Paulo Radiology PortugueseDepartament Institute of Oncology IPOL-FG Portuguese Lisboa. Portugal Institute of Oncology IPOL-FG Lisboa. Portugal 1

2 INTRODUCTION Desmoplastic small round cell tumor (DSRCT) is a rare malignant tumor first described in 1989 by Gerald and Rosai, with its radiologic findings only reported in few cases. It s included in a group of tumors classified as small round blue cells together with Hodgkin lymphoma, neuroblastoma, rhabdomyosarcoma and Ewing sarcoma. This tumor preferentially involves serous membranes especially the peritoneum and affects mainly male adolescents and young adults. On computed tomography (CT) images it presents in a characteristic fashion with one or multiple soft tissue density heterogeneous lobulated masses located in the peritoneum without an intra-abdominal organ origin. The prognosis is poor with low survival rates and the treatment is based on surgery and combined chemo-radiotherapy. In this report, we describe CT findings in tree patient with intra-abdominal DSRCT. 2

3 MATERIALS AND METHODS In our retrospective study were reported 3 cases with abdominal DSRCT diagnose confirmed by histology between 1996 and All the patients were submitted to fine needle biopsy guided by CT and definitive diagnosis were made upon immunohistochemical and cytogenetic analysis. INTRODUCTION The authors retrospectively reviewed the clinical and radiological findings, with special attention to the size, localization and other characteristics of the tumor as its enhancing after IV contrast administration and presence of calcifications. 3

4 RESULTS Radiologic Findings Case 1 The first case was diagnosed in September 1996 in a 14 year-old boy with a 1-month history of epigastric mass. Physical examination showed asymetrical abdomen with a bulge in the epigastrium with several nodules over the liver. The liver was palpated 10 cm of the costal rim. Laboratory findings showed sligthly elevated hepatic enzymes. Abdomino-pelvic CT scan show the presence of a heterogeneous soft tissue mass, with sparse calcification foci within, localized intraperitoneally in the retro-vesical space and measuring 4 x 4 cm. It was identified multiple hepatic metastasis with diameters of 6-4 cm as well as multiple adenopathies in celiac and retroperitoneal ganglionar chains, partially calcified. There was no evidence of ascitis (Figure 1). 4

5 A B Fig year-old male teenager with epigastric palpable mass. A. Abdominal CT scan after IV contrast injection shows hepatomegalia with multiple partially calcified metastasis. B. Pelvic CT scan shows tumoral mass in retro-vesical space, displacing the rectum posteriorly and showing punctate calcifications within it ( arrow). 5

6 Case 2 The second case described was diagnosed in November 2004 in a 26-year-old man presented with a 2-month history of progressive abdominal distension and loss of weigh. Physical examination confirmed a huge and firm abdominal mass. Laboratory findings were normal. Abdominal CT examination showed a huge homogeneous soft tissue mass, occupying almost all peritoneal cavities, with discrete enhancing after IV contrast administration and marked intratumoral vascularization, carrying mass effect on adjacent intraperitoneal organs, displacing intestinal loops centrally. It was also noted small amount of per-hepatic ascitis. There were no signs of metastatic lesions nor abdominal adenopathies (Figure 2). 6

7 A A B B 26-year-old young adult presented with abdominal distention and loss of weigh. A y B. Abdomino-pelvic CT examination with IV contrast administration showed diffuse infiltration of the whole peritoneum by a soft tissue density mass and small amount of ascitis. It was noted marked mass effect on intra-abdominal organs with central displacement of intestinal loops. There is marked tumoral vascularization. 7

8 Case 3 The third case was described in April 2007 in a 11-year-old boy with a 20-days history of a mass in the left upper abdomen. Physical examination confirmed a firm abdominal mass in the left upper quadrant to 3 cm of the costal rim. Laboratory tests were normal. Abdominal CT showed a polilobulated heterogeneous soft tissue solid mass, with cystic areas within, localized in the peritoneum, between the stomach and the pancreas, measuring 10,5 x 9 cm. It was identified multiple hepatic metastasis and mesenteric adenophaties. There was no evidences of ascites or extra-abdominal metastasis (Figure 3). 8

9 Fig year-old boy with palpable mass in left upper abdominal quadrant. A. - abdominal CT scan after i.v. contrast administration shows huge inhomogeneous soft tissue density mass localized intraperitoneally between the pancreas and the stomach. B. - Reconstruction in the coronal plane where it can be appreciated anatomic relationships of the tumoral mass as well as the secondary hepatic deposits ( arrow ). 9 ICR 2008 June 5-8 Marraesh

10 Histopathologic Findings Microscopic analysis of the samples obtained showed the presence of sharply demarcated and cohesive nests of small round cells with hyperchromatic nuclei surrounded by thick bands of hypocelular fibrous desmoplastic stroma (Figure 4). Immunocytochemistry studies showed the presence of multiple epithelial (cytokeratin, EMA in three cases), mesenchymal (Vimentin in two cases) and neuronal markers (enolase neuro-specific in two cases) and also CD99 (positivity of in two cases), in the tumoral cells allowing the differentiation of DSRCT from other small round cell neoplasic entities. The presence of specific translocation t (11;22)(p12;q13) in cytogenetic study was present in the three cases. 10

11 Fig.4- Photomicrograph (Hematoxylin-eoxin stain x400) shows nests of small round blue tumoral cells surrounded by desmoplastic stroma 11

12 DISCUSSION The DSRCT is a rare and aggressive neoplasm that involves preferentially serous membranes and affects in the majority of cases adolescents and young adults with ages ranging for 3 to 48 year-old (mean age 21 years-old) predominantly male gender (male/female: 3/1) [1,2]. This tumor belongs to a family of small round blue cells where are included neuroblastoma, rhabdomyosarcoma, ewing sarcoma and non-hodgkin lymphoma [2,3,4]. Although this entity has predilection for the peritoneum it can be also found in other serous membranes as pleura and paratesticular serous [3]. The first case was published by Gerard and Rosai in 1989, with just few cases reported in literature [2]. Clinical intra-abdominal DSRCT manifestations are non-specific with vague abdominal pain and the presence of palpable abdominal or pelvic mass occurring more often [1,3,5]. Other symptoms like intestinal obstruction, hidronefrosis or weight loss can be found as well. 12

13 In order of this lack of specificity the patients are oriented to a radiological study, mainly ultrasonography and CT, with the latter technique being the one that rises diagnostic suspicion of this entity [1,2]. On abdominal CT DSRCT typically presents as one or several well-defined lobulated masses, with soft tissue density but heterogeneous, presenting hypodense areas related to necrosis and hemorrhagic foci, with peritoneal localization without evident abdominal organ origin [1,3,5]. It may be possible find small calcification foci in these tumors and their metastasis [2,3]. At the time of diagnosis is often observed disseminated disease with multiple peritoneal implants, hepatic metastasis and/or abdomino-pelvic adenopathies. Hepatic metastases have a strong correlation with the existence of a masse in the retro-vesical space [2]. It s rare the occurrence of pulmonary, extra-abdominal lymphatic and bone metastasis. Ascites diffuse peritoneal thickening and hidronefrosis caused by ureteral obstruction can occur in advanced stages of disease [2,3]. 13

14 Differential diagnosis of radiological findings must be made with other entities that present with multiple peritoneal masses, including tumoral and inflammatory pathology, and is influenced by the age of patient at the time of presentation. In children we should think in rhabdomyosarcoma, non-hodgkin lymphoma, neuroblastoma, ewing sarcoma and wilms tumor [1,3]. In adolescents and young adults we should also consider malignant mesothelioma, neuroendocrine carcinomas, peritoneal carcinomatosis, peritoneal leyomiomatosis, intra-peritoneal desmoid tumor and peritoneal tuberculosis [1]. To achieve definite diagnosis is necessary histological confirmation by biopsy and it is made upon the histological, immunohistochemical and genetical characteristic findings. Visualization in histochemical study of small round tumoral cells nests with hyperchromatic nuclei within a hyperchromatic hypocellular stroma, the presence of immunopositivity for epithelial markers (Keratyn, EMA), mesenchimal markers (Vimentin, Desmin) and neural markers (neuronal-specific enolase) in tumoral cells as well as the existence of cytogenetic changes namely translocation t (11:22)(p12:q13) are diagnostic of this entity [3,6-10]. 14

15 DSRCT treatment consists in radical surgery not being possible sometimes to achieve a complete tumor resection, chemotherapy and extended radiotherapy [1]. The prognosis is poor with frequent recurrences and high rate of mortality, with mean survival rates of 17 months [1,2]. CONCLUSION 1. The radiological characteristics of DSRCT are non-specific, but it usually presents on CT images as multiple intra-peritoneal masses of soft tissue density, without apparent intra-abdominal organ origin, with disseminated disease at the time of diagnosis. 2. Although CT images are not specific, this technique as an essential role in the diagnosing and staging this entity. 3. The definitive diagnosis is always histopathological based on immunohistochemical and cytogenetic characteristics. 15

16 BIBLIOGRAPHICAL REFERENCES 1-Pickhardt PJ, Fisher AJ, Balfe DM, Dehner LP, Phyllis CH. Desmoplastic Small Round Cell Tumor of the Abdomen: Radiologic- Histopatologic correlation. Radiology. 1999; 210: Bellah R, Suzuki-Bordalo L, Brecher E, Ginsberg JP, Pawel MJ. Desmoplastic Small Round Cell Tumor in the Abdomen and Pelvis: Report of CT Findings in 11 Affected Children and Young Adults. AJR. 2005; 184(6): Chouli M, Viala J, Dromain C, Fizazi K, Duvillard P, Vanel D. Intra-abdominal desmoplastic round cell tumors: CT findings and clinicopathological correlations in 13 cases. European Journal of Radiology. 2005; 54: Varma D, Mc Daniel K, Ordonez N, Granfield C, Charnsangavej Ch, Wallace S. Primary malignant small round cell tumor of the abdomen: CT findings in five cases. AJR. 1992; 158: Tateishi U, Tadashi H, Masahiko K, Toshio O, Hitoshi I, Moriyama N. Desmoplastic Small Round Cell Tumor: Imaging Findings With Clinicopathologic Features. J. Comput Assist Tomogr. 2002; 26(4): Saab R, Khoury J, Kasin M, Davidoff A, Navid F. Desmoplasic Small Round Cell Tumor in Childhood: The St. Jude Children s Research Hospital Experience. Paediatric Blood Cancer. 2007; 49: Frappaz D, Bouffet E, Dolbeau D, Bouvier R, Carrie C, Louise D et al. Desmoplastic Small Round Cell Tumors of the abdomen. Cancer. 1994; 73: Devaney K. Intra-abdominal Desmoplastic Small Round Cell Tumor of the peritoneum in a Young Man. Ultraestructural Pathology. 1994; 18: Chang F. Desmoplasic Small Round Cell Tumors: Cytology, Histologic and Inmunohistochemical Features. Arch Pathol Lab Med. 2006; 130: Pasquinelli G, Montanaro L, Martinelli G. Desmoplastic Small Round Cell Tumor: A Case Report on the Large Cell Variant with Inmunohistochemical, Ultraestructural and Molecular Genetic Analysis. Ultraestructural Pathology. 2000; 24:

17 CORRESPONDING AUTHOR: Dr. Sergio Eiriz Martínez Serviço de Radiología. Hospital Central de Faro Rua Leao Penedo s/n Faro.Portugal 17