Proximal-Type Epithelioid Sarcoma with Unusual Morphology: A Diagnostic Challenge with Detailed Immunohistochemical Workup

Suguna Badiginchala; Aruna kumari Prayaga; Rukmangadha Nandyala; Manilal.B

doi:10.21276/apalm.3739

Authors

Suguna Badiginchala Department of Pathology, Sri Venkateswara Institute of Medical Sciences (SVIMS), Tirupati, Andhra Pradesh, India
Aruna kumari Prayaga Department of Pathology, Sri Venkateswara Institute of Medical Sciences (SVIMS), Tirupati, Andhra Pradesh, India
Rukmangadha Nandyala Department of Pathology, Sri Venkateswara Institute of Medical Sciences (SVIMS), Tirupati, Andhra Pradesh, India
Manilal.B Department of Surgical Oncology, Sri Venkateswara Institute of Medical Sciences (SVIMS), Tirupati, Andhra Pradesh, India

DOI:

https://doi.org/10.21276/apalm.3739

Keywords:

epithelioid sarcoma, proximal type, ini1 loss, unusual morphology

Abstract

Background:An uncommon and aggressive soft tissue sarcoma, Epithelioid sarcoma (ES) has a significant risk of recurrence and metastasis. The proximal variant overlaps with other epithelioid malignancies, it can be diagnostically challenging particularly in young patients. Case Presentation:We report a single-patient case of a 14-year-old male with a painful deep-seated calf mass. Trucut biopsy showed deceptively bland epithelioid–rhabdoid cells with lymphocytic admixture. After Immunohistochemistry (IHC), lesion was reported as a polygonal cell neoplasm on biopsy. Wide local excision was performed, morphology showed myxoid matrix making it more difficult to diagnose and extended IHC demonstrated PanCK and EMA positivity with complete loss of INI1, while S100, GFAP, CD34, Desmin, SALL4, and CD138 were negative, confirming proximal-type epithelioid sarcoma. Conclusion:This case emphasizes that proximal-type epithelioid sarcoma may present with deceptively bland histology and unusual myxoid stromal changes. Definitive diagnosis requires extended immunohistochemical panel, particularly assessment of INI1 loss.

References

1. Enzinger FM. Epitheloid sarcoma. A sarcoma simulating a granuloma or a carcinoma. Cancer.1970;26:1029–41.

2. Rekhi B, Gorad B.D, Chinoy R.F. Clinicopathological features with outcomes of a series of conventional and proximal-type epithelioid sarcomas, diagnosed over a period of 10 years at a tertiary cancer hospital in India. Virchows Arch. 2008;453:141–53.

3. Yoshida A, Asano N, Kawai A, Kawamoto H, Nakazawa A, Kishimoto H, Kushima R. Differential SALL4 immunoexpression in malignant rhabdoid tumours and epithelioid sarcomas. Histopathology. 2015 Jan;66(2):252-61.

4. Kohashi K, Izumi T, Oda Y, Yamamoto H, Tamiya S, et al. Infrequent SMARCB1/INI1 gene alteration in epithelioid sarcoma: a useful tool in distinguishing epithelioid sarcoma from malignant rhabdoid tumor. Hum Pathol. 2009;40:349–55.

5. Modena P, Lualdi E, Facchinetti F, Galli L, Teixeira MR, et al. SMARCB1/INI1 tumor suppressor gene is frequently inactivated in epithelioid sarcomas. Cancer Res. 2005;65:4012–19.

6. Asanova M, Ferrari A, Collini P, et al. Epithelioid sarcoma in children and adolescents: a report from the Italian Soft Tissue Sarcoma Committee. Cancer. 2006;106:708–17.

7. Touati N, Schöffski P, Litière S, Judson I, Sleijfer S, van der Graaf WT, Italiano A, Isambert N, Gil T, Blay JY, et al. European organisation for research and treatment of cancer soft tissue and bone sarcoma group experience with advanced/metastatic epithelioid sarcoma patients treated in prospective trials. Clinical profile and response to systemic therapy. Clin Oncol (R Coll Radiol). 2018;30:448–454.

8. Jones RL, Constantinidou A, Olmos D, Thway K, Fisher C, Al-Muderis O, Scurr M and Judson IR. Role of palliative chemotherapy in advanced epithelioid sarcoma. Am J Clin Oncol. 2012;35:351–57.

9. Thway K, Jones RL, Noujaim J, Fisher C. Epithelioid Sarcoma. Diagnostic Features and Genetics. Adv Anat Pathol. 2016;23(1):41-49.

10. Zhang Y, Liu F, Pan Y, Liang J, Jiang Y, Jin Y. Clinicopathological analysis of myxoid proximal-type epithelioid sarcoma. J Cutan Pathol. 2018;45(2):151-55.