Primary PEComa of the bladder treated with primary excision and adjuvant interferon-alpha immunotherapy: a case report

Abstract

Background: Perivascular epithelioid cell tumors (PEComas) are rare mesenchymal neoplasms of uncertain malignant potential, which have in common the co-expression of muscle and melanocytic immunohistochemical markers.

Case presentation: A 48-year-old man presented with dysuria, passage of urinary sediment and lower abdominal discomfort. A three centimeter mass was identified by cystoscopy in the posterior midline of the bladder. Computerized tomography suggested an enterovesical fistula. The patient underwent laparotomy, partial cystectomy and partial small bowel resection. Pathological examination revealed PEComa of the bladder. The patient underwent adjuvant interferon-alpha immunotherapy. Subsequent follow-up procedures, including cystoscopy and imaging, have not revealed evidence of recurrence. The patient is clinically free of disease 48 months after surgery.

Conclusion: This case represents the second documented PEComa of bladder and demonstrates that adjuvant therapies, including anti-angiogenic and immunotherapy, may be considered for patients with locally advanced or metastatic genitourinary PEComa.

Figure 1

Tumor cells were mainly epithelioid with abundant eosinophilic and granular cytoplasm. Occasional nuclear inclusions were present (hematoxylin-eosin, original magnification ×400).

Figure 2

Tumor cells demonstrated strong and diffuse cytoplasmic positivity for HMB45 and Melan-A (Melan-A immunoperoxidase, original magnification ×400).

Figure 3

Tumor cells showed strong and diffuse membranous positivity for smooth muscle actin (smooth muscle actin immunoperoxidase, original magnification ×400).