Clinicopathologic features of scrotal leiomyosarcoma: single institutional experience of ten cases

Scrotal leiomyosarcoma arises from the subcutaneous smooth muscle layer and is an exceptionally rare disease process, with only six patients in the largest reported case series. This rarity creates uncertainties regarding diagnosis, surgical management, and clinical outcomes. Our purpose was to retrospectively describe our institutional experience with scrotal leiomyosarcoma from 2010 to 2022. Slides were reviewed with case inclusion requiring both nuclear atypia and mitotic activity. Ten patients with scrotal leiomyosarcoma were identified. Clinical impression included scrotal cyst in nine cases. The median age at diagnosis was 52 years (range: 29-75 years). The mean tumor size was 1.6 cm (range: 0.4-3.7 cm). Margins were positive in three cases and close in one case, prompting four re-excisions. The mean mitotic rate was 2.3 per 10 high-power field (range: 1-11), with mean Ki67 of 4.6% (range: 1-15%). Nine of the tumors were grade 1, while 1 was grade 2. Four patients had disease-specific follow-up. The remaining six patients have not had disease-specific surveillance. None of the ten patients have shown evidence of recurrence (median follow-up: 75 months, range: 0-116 months). Our series demonstrates that scrotal leiomyosarcoma has a deceptive clinical presentation with a wide age range and small tumor size. With complete surgical resection, scrotal leiomyosarcoma has an excellent prognosis and rigorous follow-up or adjuvant treatment is not likely to be necessary. Cases with unusual clinical or pathologic findings, such as large tumor size or high mitotic rate, may merit more intensive disease-specific surveillance.