Proximal-Type Epithelioid Sarcoma in the Groin Presenting as a Diagnostic Dilemma

Abstract

Epithelioid sarcoma is an uncommon soft-tissue sarcoma typically presenting as a subcutaneous or deep dermal mass in the distal extremities of young adults. Lately, a 'proximal' subtype has been described, which occurs in the pelvic and genital areas of somewhat older individuals and tends to behave more aggressively than the conventional subtype. The correct diagnosis of this subtype is essential, since this tumor can be easily mistaken for other malignant tumors that exhibit epithelioid morphology. We report a case of proximal-type epithelioid sarcoma that presented as an inguinal mass in a 47-year-old man. Histologically, the tumor consisted of diffuse sheets of epithelioid cells with scattered rhabdoid morphology. By immunohistochemistry, the neoplastic cells expressed cytokeratin, epithelial membrane antigen, vimentin, CD34, CD99 and showed complete loss of nuclear INI1 protein expression. Fluorescence in situ hybridization was considered borderline for 22q deletion. We present this case to emphasize the importance of diagnosing this uncommon tumor and the role of INI1 immunohistochemistry in establishing the diagnosis.

Proximal-type epithelioid sarcoma: a new case report and literature review

“…Fisher et al [ 11 ] emphasize the importance of using immunohistochemicals markers to the diagnostic of specific soft tissue tumors specially co-expression of CD34 and cytokeratins in PES cells. Mannan et al [ 12 ] report a case of PES in a 47-year-old man, to emphasize the importance of diagnosing of this challenging tumor and the role of immunohistochemistry in establishing the diagnosis. Wide local excision with adequate margins (at least 2 cm) is recommended [ 13 ]; adjuvant radiotherapy is advocated in high-grade tumors or inadequate surgical margins [ 14 ], and also due to high incidence of local recurrence and distant metastasis [ 10 ], However it is controversial and it did not show statistically significant reduction in mortality [ 15 ].…”

Clinicopathological Characteristics, Treatment, and Survival in Patients Diagnosed With Proximal-Type Epithelioid Sarcoma: A Case Report and Systematic Review

“…Regarding treatment, 19 patients were treated surgically by wide local excision [1,4,11,12,19,[25][26][27][28][29][30][31][32][33][34], five with surgery plus lymphadenectomy [18,24,[35][36][37], seven underwent surgery and adjuvant radiotherapy [17,20,21,36,38,39], one underwent surgery and chemotherapy [26], six had surgery, chemotherapy, and adjuvant radiotherapy [13,16,17,[40][41][42], four underwent surgery, lymphadenectomy, and radiotherapy [23,36,43,44], one had surgery, lymphadenectomy, and chemotherapy [15], two underwent surgery, lymphadenectomy, radiotherapy, and chemotherapy, three received palliative radiotherapy and chemotherapy [36,45,46], and four underwent treatment with chemotherapy alone [9,10,33]. However, one patient, with metastases at presentation, received only palliative care [3] and two patients refused treatment...…”

“…The presence of hemorrhage [15,17,22,33,40,42] and necrosis [10,[15][16][17][18][19][21][22][23][25][26][27][32][33][34]36,37,[40][41][42]47] were common findings present in eight and 23 cases, respectively. High mitotic activity was reported in 18 tumors [3,4,10,12,16,18,19,22,24,25,31,32,35,37,[40][41][42], and in four of them, more than 20 mitoses were observed per 10 high-power fields [4,22,35,40]. Vascular invasion was reported in four cases [22,32,…”

“…In most cases, the tumor presents as single or multiple nodules with slow, progressive, and painless growth [1,11,12,16,24,[27][28][29][30]32,33,[36][37][38][39][40][44][45][46][47]. However, it can sometimes be accompanied by superficial ulceration, hemorrhage, necrosis, and plaques [3,10,11,18].…”

“…The proximal subtype presents a more aggressive behavior, has higher rates of recurrence and metastasis, and worse prognosis and mortality [5,[8][9][10][11]. Diagnosis is made through histological and immunohistochemical analysis, which shows epithelioid-type cells, rhabdoid, or a mixed phenotype, and the presence of immunoreactivity for cytokeratins, vimentin, and epithelial markers [5,12,13]. About 90% of these tumors, in both subtypes, show loss of nuclear expression of integrase interactor 1 (INI1) [12,14].…”