Epithelioid sarcoma with multiple lesions on the left arm: a case report

Area of Science:

• Oncology
• Pathology

Background:

• Epithelioid sarcoma is a rare, high-grade soft tissue malignancy with high rates of recurrence and metastasis.
• It predominantly affects adolescents and young adults and is often misdiagnosed as benign conditions in early stages.

Observation:

• A case of a 74-year-old Japanese woman with epithelioid sarcoma initially misdiagnosed as a fungal infection is presented.
• Rebiopsy showed atypical epithelioid cells in the dermis with lymphocyte infiltration.
• Immunohistochemistry revealed tumor cell positivity for vimentin, CD5.2, EMA, and ERG, with loss of INI1 nuclear expression.

Findings:

• The study highlights diagnostic challenges in epithelioid sarcoma, particularly in older adults.
• Immunohistochemical markers like vimentin, CD5.2, EMA, ERG, and INI1 are critical for accurate diagnosis.
• Loss of INI1 nuclear expression is a key indicator in epithelioid sarcoma.

Implications:

• Difficult diagnoses of epithelioid sarcoma necessitate considering repeat biopsy and immunohistochemical analysis.
• Early and accurate diagnosis of epithelioid sarcoma can improve patient outcomes.
• This case underscores the importance of considering rare diagnoses in treatment-resistant lesions.