RESUMEN
A 47-year-old man presented with a 10-year history of multiple lumps over his left upper arm and shoulder and the adjoining left side of his chest and upper back. His medical history included diabetes mellitus type 2. The patient was a farmer and used to lift sacks of grains and fertilizers onto his shoulders as part of his work, although he did not recollect any history of specific trauma. Skin biopsy revealed granulomatous reaction with Splendore-Hoeppli phenomenon, while periodic-acid-Schiff and Grocott-Gomori stains confirmed fungal elements. Sabouraud agar grew Chaetomium species, and lactophenol blue mount confirmed the fungus as Chaetomium strumarium. Radiography and computed tomography of the chest revealed intrathoracic extension of the mycetoma. The patient responded well to treatment with oral Itraconazole. Subcutaneous mycosis due to C. strumarium is rarely reported in the literature, and the intrathoracic extension makes it an even rarer entity.