Secondary Myiasis in an Immunocompetent Patient With Severe Chromoblastomycosis

This is the case of chronic chromoblastomycosis (CBM) in a 61-year-old male from the Dominican Republic (DR) with extensive cutaneous eruptions over multiple areas of the body including bilateral lower extremities and the flank extending to the back. A 61-year-old male with a history of morbid obesity, chronic kidney disease stage III, and well-controlled hypertension presented to the family medicine clinic for the evaluation of chronic painful skin lesions on his legs and torso. The lesions began 19 years prior, following a flood in the Dominican Republic (DR) where he was living at the time. He described the initial lesion as a dark flat spot that never healed, despite various home remedies. It began on his distal lower left extremity and slowly became more nodular and spread over his entire lower left extremity. Over the years, he continued to develop more nodular lesions on both legs and his left flank. Physical exam revealed multiple hyperkeratotic fungating nodules and papules on the bilateral lower extremities as well as the left flank. Physical exam of the left lower extremity showed multiple hyperkeratotic fungating nodular skin lesions. No biopsies were done at that visit. Three weeks after his initial presentation, the patient presented to the emergency department with complaints of bloody discharge and "maggots" in his leg wounds. On physical exam, there was evidence of two infected pedunculated lesions with surrounding erythema and maggots coming out of the wound on the left lower extremity. Using scissors, one of the lesions was excised, resulting in complete removal of the maggots. The tissue was sent to pathology for assessment and acid-fast bacilli (AFB) smear. Pathology report showed skin with marked papillary epidermal hyperplasia with prominent parakeratosis, pseudoepitheliomatous hyperplasia, granulation tissue, and extensive dermal acute inflammation with microabscesses. The larvae had a dense cuticle with viable internal organs and striated muscle. There was no evidence of malignancy, and AFB smear was negative. The patient was continued on Keflex and referred to infectious disease for further evaluation. Infectious disease started the patient on ivermectin 3mg four times a day due to the possibility of chronic larval migrans. A shave biopsy was performed by dermatology, and pathology showed marked papillary epidermal hyperplasia with parakeratosis and prominent pseudoepitheliomatous squamous hyperplasia. The dermis showed extensive chronic and focal acute inflammation with micro-abscesses and scattered multi-nucleated foreign body giant cells. Scattered within the pyogranulomatous inflammation in the dermis were singly and clusters of brown pigmented yeast forms, some engulfed by foreign body giant cells. Special stains (GMS and PAS-D) highlighted fungal organisms. These results in the context of extensive chronic lesions were compatible with chromoblastomycosis. Given this diagnosis, the decision was made to continue on itraconazole 200mg oral twice daily. Dermatology also began physical treatment with liquid nitrogen cryotherapy with topical Mupirocin ointment to be applied daily. This treatment is currently ongoing and shows significant decreases in severity of lesions as noted in decreased pain, significant flattening of the lesions. The patient is reassessed with repeat fungal cultures every six weeks.