A Rare Manifestation of Tuberculosis in a Renal Transplant Patient: A Case Report

Cutaneous lesions in the presence of fever in patients undergoing immunosuppressive therapy are a diagnostic challenge and may represent manifestations of multiple diseases, such as fungal infections, nocardiosis, lymphoproliferative diseases, zoonosis, and tuberculosis. The authors report a case of a 66-year-old white man with chronic kidney disease since 2014 (chronic pyelonephritis) who had a renal transplant in the previous 6 months. Induction therapy was performed with thymoglobulin, and his current immunosuppression scheme included tacrolimus, mycophenolate mofetil, and prednisolone. The patient had no history of pulmonary tuberculosis. The patient presented with 2 cutaneous lesions, localized on the back and abdomen, that appeared to be firm, painful, subcutaneous, erythematous nodules with an approximately 5 cm diameter overlying an infected focus and purulent material inside. The patient also had a fever and fatigue. Blood analysis showed pancytopenia with an elevation of inflammatory markers and graft dysfunction. Tissue cultures and skin biopsy with histological analysis were performed. Histopathology of the lesion showed a nonspecific inflammatory infiltrate without granulomas, and acid-fast bacillus staining was negative. Nevertheless, serum QuantiFERON testing was positive. But polymerase chain reaction finally confirmed the presence of Mycobacterium tuberculosis, which confirmed the diagnosis of cutaneous tuberculosis. A chest computed tomography scan showed a lung pattern of miliary tuberculosis. The patient was treated with multidrug tuberculosis therapy, resulting in lesion clearance after 3 weeks. Tuberculosis is a serious infection, especially in high-risk patients, such as those in an immunocompromised state. The incidence of cutaneous tuberculosis is rare, but it should be considered in patients presenting with atypical skin lesions suggestive of an underlying infectious etiology.