Pigmented squamous cell carcinoma in situ of the conjunctiva in 5 cases

Abstract

Purpose: To describe 5 patients with pigmented conjunctival squamous cell carcinoma in situ.

Design: Retrospective noncomparative case series.

Participants: Five patients.

Methods: Clinical and histopathologic features were reviewed.

Main outcome measures: Relationship of clinical and histopathologic features to carcinoma pigmentation.

Results: All 5 patients were male. Two were Hispanic, 2 were Caucasian, and 1 was Asian Indian. Localized racial melanosis was evident in 3 cases and no case showed diffuse racial melanosis. The tumor showed leukoplakia (n = 1) and was at the temporal limbus (n = 4) or nasal limbus (n = 1). The mean tumor basal dimension was 9.2 mm and mean thickness was 3.2 mm. Brown pigment was present deep within the tumor in all 5 cases, involving 50% to 90% of the mass. In each case, pigmented squamous cell carcinoma was suspected; melanoma was a second possibility. Histopathology revealed in situ squamous cell carcinoma (conjunctival intraepithelial neoplasia) with pigmented dendritic melanocytes in all 5 cases. Pigment was also found within neoplastic cells (n = 2). After surgical resection, there was no recurrence over mean follow-up of 23 months.

Conclusions: Squamous cell carcinoma in situ can manifest as a pigmented tumor, resembling melanoma, in both Caucasians and non-Caucasians, primarily due to intratumoral pigmented dendritic melanocytes.