PRESENTATIONA 64-year-old woman presented with erythematous nodules on the left hand, forearm, and upper arm developing over 2 months. A single nodule was first noted on the dorsum of the left hand, followed by progressive development of several similar nodules on the left forearm and upper arm. She also reported a small cut on the left fifth digit with persistent pain, redness, and drainage of clear fluid for several months. Over the course of her illness, the patient had been treated with amoxicillin/clavulanate and then cephalexin but did not notice any improvement. She denied any medical problems, toxic habits, recent trauma to the hand, or exposure to marine water. She was a native of China and had been living in New York City for 29 years with no recent international or domestic travel. She reported gardening at home on a regular basis and said she had been applying plant leaves and thorns to the area of injury on her hand as part of a traditional Chinese remedy. Review of systems was negative for fever, night sweats, weight loss, or joint swelling.
ASSESSMENTOn physical examination, the patient's temperature was 37 C, blood pressure was 168/84 mm Hg, and pulse was 80 beats/min. Multiple subcutaneous erythematous nodular lesions were noted on the left upper extremity extending proximally in a linear fashion from the dorsum of the left hand to the forearm and upper arm ( Figure A). A small cut was observed on the palmar aspect of the left fifth digit with mild surrounding erythema, swelling, and minimal drainage of clear fluid. There was no epitrochlear or axillary lymphadenopathy, and the remainder of the physical examination results were normal. The patient had a total white blood cell count of 8800/mL with a normal differential count. Hepatic and renal function were normal.
DIAGNOSISThe patient was administered empiric itraconazole for Sporothrix schenckii infection (sporotrichosis) acquired during gardening. Two weeks into the course of therapy, the patient's skin lesions were unchanged with the exception of a few small nodules on the forearm that showed mild interval decrease in size. Biopsy of a nodule was performed. Histopathology showed dense inflammatory infiltrate in the dermis with numerous neutrophils and focal necrosis with surrounding histiocytes, lymphocytes, and plasma cells. Numerous acid-fast positive bacilli were seen on both acidfast and Fite stains. Grocott's methenamine silver stain and periodic acid-Schiff stains were negative for fungi. Culture of the biopsy tissue grew Mycobacterium marinum. On further questioning, the patient recalled antecedent trauma to the left hand from a fish scale while cooking.Our patient's case highlights a common diagnostic dilemma. There are no pathognomonic clinical features of Mycobacterium marinum infection, and delay in diagnosis is common. 1 Most patients present with papules or nodules of the upper extremity. Less commonly, abscess and ulcer formation are seen. 2 Lymphocutaneous spread similar to sporotrichosis, nocardia, and other nontuberculous myc...