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Year : 2020  |  Volume : 63  |  Issue : 2  |  Page : 342-344
Catechism (Quiz 8)

Department of Pathology, Seth G.S. Medical College and King Edward Memorial Hospital, Mumbai, Maharashtra, India

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Date of Web Publication18-Apr-2020

How to cite this article:
Agnihotri M, Kothari K, Khadilkar A. Catechism (Quiz 8). Indian J Pathol Microbiol 2020;63:342-4

How to cite this URL:
Agnihotri M, Kothari K, Khadilkar A. Catechism (Quiz 8). Indian J Pathol Microbiol [serial online] 2020 [cited 2021 Jun 13];63:342-4. Available from: https://www.ijpmonline.org/text.asp?2020/63/2/342/282681

   Part 1 Top

A 32-year-old man presented with a left cervical lymphadenopathy for one month. On examination, it was measured 2.5 cm × 2 cm, firm and nontender. There was no history of fever, weight loss, or contact with patients with tuberculosis. The routine hematological investigations were normal. Fine-needle aspiration cytology (FNAC) of the lymphnode was performed, and Papanicolaou and Giemsa stained smears were prepared [Figure 1].
Figure 1:

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  1. What is your interpretation?
  2. Which immunochemistry markers will help in the diagnosis?

   Answers of Catechism (Quiz 7) Top

  1. Malignant gastrointestinal neuroectodermal tumor (GNET)
  2. Clear cell sarcoma-like gastrointestinal tumor (CCSLGT)
  3. S100 protein
  4. EWSR1 gene rearrangement by fluorescence in situ hybridization (FISH).

   Microscopic Features Top

Histopathologic resection of the primary jejunal tumor, the peritoneal deposit, as well as the hepatic metastatic mass revealed a malignant tumor composed of round-to-polygonal/epithelioid cells arranged in nesting and perivascular arrangements with interspersed cells containing vacuolated cytoplasm. The tumor was seen involving jejunal wall in a transmural manner [Figure 1]a, [Figure 1]b, [Figure 1]c.

In addition, lymphovascular emboli and perineural invasion were noted.

By immunohistochemistry, tumor cells were diffusely positive for S100 protein while negative for synaptophysin, chromogranin, C-kit, DOG1, HMB45, melan-A, smooth muscle actin, and pan-cytokeratin (AE1/AE3) [Figure 1]d. Diagnosis of malignant GNET was offered.

Furthermore, by FISH, tumor cells showed EWSR1 gene (22q12) rearrangement, further confirming the diagnosis of GNET [Figure 2]. Subsequent sections of the liver lesion showed metastatic tumor deposits.

   Discussion Top

Malignant GNET is a rare malignant mesenchymal tumor, synonymous with CCSLGT, characterized by an aggressive clinical course, including high rates of local recurrence, metastases, and early death.[1],[2],[3] These tumors occur within a wide age range in patients presenting with abdominal symptoms, such as pain, intestinal obstruction, and mass lesion.[3] Histopathologically, differential diagnoses in such cases include clear cell sarcoma/melanoma of soft parts, Ewing's sarcoma, desmoplastic small round cell tumor, epithelioid gastrointestinal stromal tumor, malignant peripheral nerve sheath tumor, and undifferentiated round-to-epithelioid sarcomas.

Certain morphologic features, such as round-to-epithelioid cytomorphology, variable cytoplasmic vacuolation; nesting arrangement of tumor cells, presence of osteoclast-like giant cells, along with immunohistochemical markers; and molecular analysis, are required for an exact diagnosis of this tumor. Immunohistochemically, the tumor cells invariably show positive expression for S-100 protein, SOX10, and vimentin in nearly all cases; variable expression for CD56, synaptophysin, NB84, neuron-specific enolase (NSE), and neurofilament protein; and negative immunoexpression for specific markers for melanoma/clear cell sarcoma (HMB45 and melan-A), gastrointestinal stromal tumors (CKIT and DOG1), as well as epithelial and myoid/muscle markers, as noted in the present case.[1],[2],[3]

Very few cases of GNET confirmed with molecular and/or cytogenetic results have been documented.[3],[4] It was debated whether GNET and clear cell sarcoma of the gastrointestinal tract constitute variants of a single entity. However, lack of melanocytic differentiation in the former, in contract to the latter, has proven that both these tumors are different.[3]

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.

   References Top

Zambrano E, Reyes-Mugica M, Franchi A, Rosai J. An osteoclast-rich tumor of the gastrointestinal tract with features resembling clear cell sarcoma of soft parts: Reports of 6 cases of a GIST simulator. Int J Surg Pathol 2003;11:75-81.  Back to cited text no. 1
Rosai J. Editorial: Clear cell sarcoma and osteoclast-rich clear cell sarcoma-like tumor of the gastrointestinal tract: One tumor type or two? Melanoma or sarcoma? Int J Surg Pathol 2005;13:309-11.  Back to cited text no. 2
Stockman DL, Miettinen M, Suster S, Spagnolo D, Dominguez-Malagon H, Hornick JL, et al. Malignant gastrointestinal neuroectodermal tumor: Clinicopathologic, immunohistochemical, ultrastructural, and molecular analysis of 16 cases with a reappraisal of clear cell sarcoma-like tumors of the gastrointestinal tract. Am J Surg Pathol 2012;36:857-68.  Back to cited text no. 3
Alyousef MJ, Alratroot JA, ElSharkawy T, Shawarby MA, Al Hamad MA, Hashem TM, et al. Malignant gastrointestinal neuroectodermal tumor: A case report and review of the literature. Diagn Pathol 2017;12:29.  Back to cited text no. 4

Correspondence Address:
Mona Agnihotri
Department of Pathology, Seth G.S. Medical College and K.E.M. Hospital, Parel, Mumbai - 400 012, Maharashtra
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/IJPM.IJPM_15_20

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