Melanoacanthoma: Uncommon presentation of an uncommon condition
A 62-year-old male was presented with a blackish verrucous outgrowth over the left inguinal region since the past 8 years. It started with a pigmented elevated lesion at the same site that gradually increased to the current size. Other than occasional pruritus at the sites of occlusion and the feeling of heaviness while walking, the lesion had remained largely asymptomatic. There was no bleeding from the lesion. The patient was a chronic smoker since the past 30 years. There were no concomitant comorbidities or medications.\nThe systemic examination of the patient was normal. Dermatological examination revealed a single well-defined sessile deeply pigmented verrucous mass measuring 15 cm by 8 cm over the left inguinal region extending onto the medial aspect of the scrotum []. There were areas of depigmentation and maceration at the sites of friction. The mass was non-tender and there was no associated lymphadenopathy. Mucus membrane examination was normal.\nA clinical differential diagnosis of melanoacathotic variant of seborrheic keratosis, pigmented variant of seborrheic keratosis, giant condyloma acuminata and verrucous carcinoma were thought of.\nLaboratory investigations including routine hematological and biochemical investigations comprising hepatic and renal profiles and urine examination were all within normal limits. VDRL and HIV testing of the patient were non-reactive.\nHistopathological examination of the biopsy specimen revealed hyperkeratosis, papillomatosis, acanthosis, with melanocytes spanning all layers of the epidermis with abundant melanin. The base of the tumor was lying in a straight line with the surrounding normal epidermis. Small horn cysts were seen. Pigment incontinence was seen in the dermis. High power microscopy revealed cells with ovoid nuclei and cleared cytoplasm with abundance of melanin [Figures and ]. Dendritic melanocytes were demonstrated by the Masson Fontana silver impregnation stain []. All these findings confirmed the diagnosis of melanoacanthoma.\nPatient was further referred to the department of plastic surgery where complete excision with adequate margin and suturing was done [].