A 33-year-old male patient resident of Manguinhos - Rio de Janeiro - Brazil was diagnosed 18 months ago with polymyositis and was irregularly taking methotrexate (15mg/weak) with prednisone (40 mg/day); however, he failed to attend medical follow-up visits regularly. One year ago, he was hospitalized with pulmonary tuberculosis. He was prescribed rifampicin, isoniazid and pyrazinamide and completed a six-month treatment period. 
Six months later, he was admitted at the Hospital with painful warm nodules of various sizes on his body in addition to gummatous lesions developed two months earlier (Figures 1,2 and 3). He presented intermittent fever which responded to metamizole. There was throbbing pain in his limbs, aggravated by movement and alleviated by resting. He also complained of muscle weakness in pectoral and pelvic girdle. 
At admission, he had tachypnea, tachycardia and fever. Lymphadenopathy was absent and the blood pressure was normal. The laboratory tests showed leukocytosis (21,100 leukocytes), thrombocytosis (573,000 platelets) and normocytic normochromic anemia. Lactate dehydrogenase (LDH) levels were 515 U/I and creatine phosphokinase (CPK) 282 IU/l. Chest x-ray revealed no abnormalities. During hospitalization, leukocytosis, thrombocytosis and normocytic normochromic anemia persisted, as well as increased LDH levels. Creatine phosphokinase returned to normal levels. 
The differential diagnosis of the nodular disease mainly considered myositis and vasculitis, methotrexate-related panniculitis, Weber-Christian disease, subcutaneous panniculitis-like T-cell lymphoma, erythema nodosum, bacterial, fungal and mycobacterial infections. 
At admission antibiotic therapy with oxacillin was initiated against infection by Staphylococcus. However, no specimen has confirmed the suspicion of diagnosis. These results hampered the investigation for presence of staphylococci bacteria and made the decision to maintain or not the antibiotics difficult. The patient's fever and skin rash persisted despite the therapy. On the seventh day of treatment, the antibiotic was changed to vancomycin at 500 mg qid intravenously for 14 days; no improvement occurred in the patient's clinical condition. 
The material collected from the lesions was studied for histopathology patterns, bacterioscopy and culture studies. 
Ultrasound confirmed a subcutaneous structural alteration on the posterior region of the upper third of the right leg, with 8 cm in size and without liquid. The possibility of purulent material being accumulated inside the lesion could not be discarded. 
Skin histopathology studies revealed acanthosis, edema of the reticular dermis, and mild infiltrate of lymphocytes with some neutrophils around vessels and skin adnexa. Panniculitis was suggested by the presence of subcutaneous necrosis of adipocytes, deposits of fibrinoid material and hyaline eosinophilic strands. Initially, aspirated secretion from the lesions was negative for acid-fast bacilli. 
One week later, a new sample showed acid-fast bacilli (+ + +). Rifampicin 600 mg qd, isoniazide 400 mg qd, pyrazinamide 2 g qd and ethambutol 1.2 g qd were initiated. Within a five-day treatment period the patient improved considerably, the fever disappeared and he was discharged. Culture studies revealed growth of Mycobacterium tuberculosis. Lesions were totally cured after 6 months.