Primary pure carcinoid tumors of the testis: Clinicopathological and immunophenotypical characteristics of 11 cases.

Primary pure carcinoid tumors of the testis (pPCTT) are rare, and there are only a limited number of studies available. In the present study we described the clinicopathological and immunophenotypical characteristics of 11 cases from our institution between 1978 and 2014, and reported our experiences of the diagnosis and treatment of these patients. The patients ranged in age from 26 to 68 years old, with a median age of 48 years. One patient (9%) was classified as pT2 and 10 (91%) were pT1. Histologically, 7 cases were diagnosed as classical carcinoid tumors, while the other 4 cases were identified as atypical carcinoid tumors. The most common growth pattern was a mixed insular, acinar, rosetted, solid and trabecular pattern. Immunohistochemical staining revealed positive expression of neuron-specific enolase in all cases, and CgA, Syn and CD56 markers in 8 (72.7%), 10 (90.9%) and 9 cases (81.7%), respectively. In addition to radical orchiectomy, 9 patients (81.7%) received a combined modality of treatment. Follow-up data were available for 8 patients. Seven were alive at the last follow-up without recurrence, and one patient succumbed to cerebral hemorrhage 7 years after surgery. In summary, localized pPCTT is a rare disease with an indolent clinical course. When a testicular carcinoid tumor is identified, a metastasis or an intestinal primary tumor should be excluded, particularly when the testicular tumor is large. A tumor size ≤6.0 cm and the histological appearance had little relation with metastatic behavior.