PEComa of soft tissues can mimic lymph node relapse in patients with history of testicular seminoma.

Perivascular Epithelioid Cell tumour (PEComa) is rare. We describe a 39-year-old man who underwent a left radical orchidectomy and adjuvant radiation therapy for a stage IA classical testicular seminoma. He was diagnosed with a mass lateral to the right common iliac artery that was considered suspicious for late lymph node relapse after 3 years of follow-up. Due to the unusual location of the mass and the equivocal findings of percutaneous biopsy, a laparoscopic pelvic lymphadenectomy was performed. Final pathology revealed PEComa of soft tissue. The patient is disease-free after 38 months of follow-up without adjuvant treatment. The presence of rare soft-tissue neoplasm should be considered in differential diagnosis of retroperitoneal masses during follow-up of germ cell tumours. Suspicious isolated recurrences of these neoplasms in unusual locations can require surgical excision to confirm diagnosis and avoid inappropriate treatment.