Tuberculosis: An unusual etiology of Baker's cyst

Abstract Baker's cyst is usually degenerative in origin, infective etiology is rare, and tubercular origin is exceptional; only 5 such cases have been reported in English literature till date. We present a case of a young female who presented with clinico-radiological features suggestive of Baker's cyst with associated posterior horn medial meniscal tear. Arthroscopic evaluation revealed suspicious synovial hypertrophy along with meniscal tear and Baker's cyst. Arthroscopic management of Baker's cyst and meniscal pathology was done along with radical synovectomy. Histopathological examination revealed epitheloid granulomas and Langhans giant cells pointing toward a tubercular etiology. Standard ATT protocol with rehabilitation was followed. The patient was asymptomatic at 1 year with complete resolution of symptoms and full range of motion. This case highlights the need to maintain high index of suspicion in cases hailing from endemic region with unusual intra-operative findings; also, it underlines the importance of routine histo-pathological examination.