ISOLATED POPLITEAL CYST TUBERCULOSIS - A CASE-REPORT

Introduction Isolated localization of tuberculosis in the popliteal cy st is an exceptional affection. Case report Mr. M.L., 18-year-old blac k moroccan, was admitted for a painful swelling of the left popliteal cyst, general state alteration and left thoracic pain. Clinical examin ation found a 5 cm on 3 cm oval tumefaction at the supero-medial part of the left popliteal hollow. No articular effusion was noted. Left kn ee X ray was normal, while ultrasound examination showed a modified po pliteal cyst. Chest X ray showed a pleural effusion. Tuberculine skin test was positive (18 mm). A subtotal resection of the cyst was perfor med, evacuating 10 mi of thick pus. The histologic examination of the cyst confirmed its tuberculosis origin. In addition the left pleural b iopsy confirmed the diagnosis of tuberculosis as well. The antibacilla r treatment based on rifampicine, INH and pyrazinamide was given durin g 6 months. The evolution was favorable at 2 years of follow-up. Discu ssion Knee popliteal cyst is frequently an expression of an inflammato ry or traumatic affection. The communication between the articular syn ovium and the serosa bursa of the lateral gastrocnemius is found in 50 per cent of cases, allowing an association of both localizations of t uberculosis. Hamabuchi described for the first time an isolated poplit eal cyst tuberculosis in 1990. This case is similar to Hamabuchi's obs ervation. Clinical and radiographical examinations were normal thus ex cluding a possible dissemination from the knee joint.