An unusual primary conjunctival plasmacytoma

A 57-year-old man with past medical history of chronic alcoholic pancreatitis was referred to the Oculoplastics Service of the Ophthalmology Clinic at Ospedale Maggiore, Trieste, for evaluation of a lower eyelid neoformation of recent onset. On examination, a sessile, reddish-pink, conjunctival lesion measuring 7 × 4 mm was observed in the middle one-third of the right lower eyelid fornix. The lesion was mobile with respect to the tarsus and displayed superficial telangiectatic vessels (A). Histopathological analysis of the excised lesion showed proliferation of mature plasma cells in a trabecular pattern. Immunohistochemistry showed positivity for CD38 (B), CD56, CD79a, CD117, CD138, MUM1/IRF4, and cyclin D1, revealing a nonsecretory plasmacytoma. Conjunctival plasmacytomas are exceedingly rare plasma cell neoplasms that can be isolated (primary) or associated with bone marrow plasmacytosis or multiple myeloma (secondary). Depending on the size and localization, treatment options include local excision, external beam irradiation, or radiotherapy after surgical excision. Long-term follow-up with periodic systemic evaluations, is necessary to confirm that conjunctival involvement is not an early manifestation of multiple myeloma. After referral for hematological evaluation, a bone marrow biopsy and PET/CT scan were performed to rule out secondary lesions; results were negative, confirming the diagnosis of primary conjunctival plasmacytoma. The patient has been monitored for 24 months after diagnosis, and no evidence of local recurrence or systemic disease has been detected.