Plasmoacanthoma of Lip-A Rare Case with Review of Literature.

Plasmoacanthoma is an extremely rare benign verrucous lesion, with few cases reported in the literature, and it often goes misdiagnosed. An attempt was made to discuss the features and compare them to reduce the diagnostic dilemma in cases of plasmoacanthoma, which mimics squamous cell carcinoma, both for the clinician and pathologist. Written informed consent was obtained from the patient for the case report. Institutional ethical clearance was obtained. A review of the literature was conducted after a PubMed search with the keyword "Plasmoacanthoma" on September 20, 2023. Nine articles were obtained, out of which two were not available. One was excluded since it was on plasma cell cheilitis. Five articles, all of which were in the English language, with a diagnosis of plasmoacanthoma were retrieved for the study. A 70-year-old female presented with an ulcer-exophytic lesion involving the lower lip, mimicking a typical squamous cell carcinoma, for which an edge biopsy of the lesion was taken to confirm. Histopathology revealed it to be plasma cell mucositis. The patient was put on the medical line of management with corticosteroids as per guidelines, with no response. A wedge excision was later done as the patient was not responding to medical therapy, and the final histopathology came out to be "plasmoacanthoma". Due to their close resemblance to malignant lesions and histologically mimicking plasma cell mucositis, such lesions often get misdiagnosed, leading to inadequate management. Various sources of literature related to plasmoacanthoma were compared, and the features and histological findings were tabulated so that if any cases were similar to the present case reports, then we could have other differential diagnoses and work accordingly. Plasmoacanthoma may be present in any age group, and the clinical features may be similar to those of squamous cell carcinoma. PCM and plasmoacanthoma are clinically and histologically mimicking conditions that should be confirmed by excisional biopsy on histopathological examination rather than incisional biopsy to avoid pathological adversity, as seen in our case. IHC with kappa and lambda light chains will help identify clonal plasma cells seen in plasmoacanthoma.