Polymorphic keratotic nodules in an immunocompetent man

Abstract

A 25-year-old male labourer presented to our institution with multiple, asymptomatic, keratotic bumps over his face, right arm, and trunk. He reported that they had started developing 6 months previously; initially a red swelling appeared over his face and subsequently, three cutaneous lesions appeared over his abdomen, chest, and right arm. There was no family history for such lesions and he did not have a history of high risk sexual behaviour. A solitary, erythematous nodule (3 cm × 3 cm) with a verrucous surface had developed on his face (fi gure A). He had a skin-coloured keratotic plaque (4 cm × 4 cm) situated over the right side of his abdomen. Another two erythematous keratotic plaques (each 1 cm × 1 cm) were situated over his chest and arm. The lesions were non-tender and free from underlying structures. He had no lesions on other areas of his body including the nasal and oral cavities, genitalia, and the perianal area. Examination of the patient’s organ systems did not reveal anything unusual. Results of routine laboratory investigations, chest radiography, and abdominal ultrasonography were normal. ELISA for HIV infection was non-reactive. The lesions were excised by radiofrequency surgery in phases. Histopathological examination of all the excised biopsy specimens revealed multiple thick-walled sporangia with numerous spores and chronic infl ammatory infi ltrate (fi gure B, C). On the basis of the clinicopathological features, a diagnosis of primary cutaneous rhinosporidiosis was made. The lesions completely healed within 3 weeks with mild residual scarring. The patient was then prescribed dapsone gel (5%) locally twice daily for 3 months to prevent relapse. The patient was followed up for 12 months after surgery without any sign of recurrence. Rhinosporidiosis is a chronic granulomatous, infective disease, mainly caused by Rhinosporidium seeberi. Although it is endemic in Sri Lanka, India, and South America, cases have been reported globally. It is transmitted by direct contact with spores through dust, infected clothing, fi ngers, swimming in stagnant water, and autoinoculation. Although nasal mucosa is the most commonly aff ected site, other mucosal surfaces and rarely other parts of the body such as skin, viscera, and brain can be involved. Defi nitive diagnosis can be made by histopathological examination. Surgical excision or electrodessication, or both, are the most common methods of treatment of cutaneous rhinosporidiosis.