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

Abstract

To describe 5 patients with pigmented conjunctival squamous cell carcinoma in situ. Retrospective noncomparative case series. Five patients. Clinical and histopathologic features were reviewed. Relationship of clinical and histopathologic features to carcinoma pigmentation. 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. 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.