Document Type : Case Report


1 Department of Dermatology, Kasturba Medical College, Manipal Academy of Higher Education (MAHE), Manipal, Karnataka, India

2 Department of Pathology, Kasturba Medical College, Manipal Academy of Higher Education (MAHE), Manipal, Karnataka, India


Actinomycotic mycetoma or actinomycetoma is a type of mycetoma caused by Nocardia and Actinomyces. It usually affects the trauma-prone areas or extremities of the body. It is associated with characteristic discharging granules and sinuses. Gram staining of discharged granules shows thin Gram-positive filaments. Histopathology of granules shows suppurative granulomas composed of neutrophils surrounding characteristic grains. Several antibiotics are effective, including co-trimoxazole, dapsone, streptomycin, trimethoprim (TMP), rifampicin, and amoxicillin-clavulanic acid. However, co-trimoxazole remains the gold-standard therapy. Actinomycetoma of the scalp has been rarely reported. Here, we report the case of an Asian male in his 50s presenting with swelling over the scalp. It had developed seven years ago after a road traffic accident and remained elusive to treatment. There were no discharging sinuses or granules characteristic of actinomycetoma. The Gram stain and Modified Ziehl-Neelsen stain from superficial swabs were negative for pathogens. Bacterial and fungal cultures of the biopsy sample were inconclusive. However, histopathology showed epidermis having focal acanthosis overlying granulation tissue with proliferating capillaries, edema, and infiltration by lymphocytes, plasma cells, neutrophils, and eosinophils along with scattered foreign body giant cells. Filamentous bacterial colonies with surrounding neutrophils were present. These features were suggestive of actinomycetoma. The patient was treated with oral doxycycline and co-trimoxazole and had a complete regression of swelling after three months of follow-up. This case highlights an unusual morphology and location of actinomycetoma, which should be considered when encountering subcutaneous swelling.