Abstract
Purpose:
Oncocytomas are benign tumors that have been reported to account for 3-8% of excised caruncle lesions. These cystic lesions grow slowly, are usually asymptomatic and occur predominantly in elderly women. Oncocytomas may be found in other glandular organs as well. Therapy is by excision. Malignancy has only been described in single cases, but not at the caruncle. It is unclear whether the tumour is of glandular or myoepithelial origin. We examined histologically all caruncular oncocytomas that have been diagnosed in our clinic between 2000 and 2012.
Methods:
Retrospective chart review of all conjunctival probe excisions performed in a single center over 12 years. Routine HE-histological analysis of all oncocytomas of the caruncle, and, if sufficient material was available, immunohistochemical analysis for pancytokeratin (pan-CK), smooth muscle antigen (SMA), lysozyme, estrogen (ER) - and progesterone receptors (PR).
Results:
In the observed period, we excised 641 conjunctival probes where one oncocytotic adenocarcinoma was diagnosed. 51 / 641 (8%) probes originated from the caruncle with 53 different pathologies. The most frequent caruncular diagnoses were nevi (22 / 53 [43%]), cysts and oncocytomas (6 / 53 each [12%]), sebaceous gland hyperplasia (5 / 53 [10%]), papillomas (4 / 53 [8%]), and others. The gender ratio of oncocytoma patients was female : male = 5 : 1. The mean age was 79 years. The diagnosis could be established by routine HE histology in all cases. Material for immunostaining was available for 3 / 6 cases. All 3 immunohistochemical patterns showed positivity for pan-CK and SMA but negativity for lysozyme, ER and PR.
Conclusions:
In our series, oncocytomas occurred more frequently (12%) than in other retrospective analyses (3-8%) and were among the second most frequent diagnoses of caruncle tumors. As reported by others, the majority originated from elderly women, but the gender preference could not be explained by positive ER or PR expression in the 3 cases eligible for immunostaining. The findings favor myoepithelial origin over glandular origin. 1 oncocytotic adenocarcinoma in 641 cases occurred distant from the caruncle, and no malignant transformation of the tumor was found in the caruncular localization.
Keywords: 474 conjunctiva •
638 pathology: human •
744 tumors