A 70-year old man with history of chronic smoking was brought to the emergency department with acute painful swelling involving his right hand and the right knee. There was history of mild fever especially at night. There was no past history of injury, gout, rheumatoid arthritis or tuberculosis. Clubbing of the finger nails were noted ipsilaterally. Movements of the fingers of the involved hand and the knee were painfully restricted. The swelling in the right hand was especially in the first web-space [Figure 1]. In the right knee the swelling was more on the medial femoral condyle. On palpation the swollen areas were grossly tender and doughy. Differential diagnoses considered by the initial physicians attending the case were gouty arthritis, septic arthritis and acute osteomyelitis. Radiographs showed pure lytic bony lesion with complete disappearance of lower two third of the second metacarpal, trapezium and trapezoid bones of the right hand [Figure 2]. Radiograph of the right knee showed pure lytic lesion of medial condyle of femur with subarticular extension [Figure 3]. Chest X-ray showed no abnormal findings. Pain was unresponsive to Non steroidal anti-inflammatory drugs and it was severe at night disturbing his sleep. Intravenous Tramadol was started the next day with partial pain relief. In view of the evolving clinic-radiological findings a new set of differential diagnosis emerged that included metastatic diseases, multiple myeloma and remote possibilities of multi-centric GCT, multi-centric osteosarcoma, brown tumors and disseminated tuberculosis. Blood tests showed anemia, raised sedimentation rate (ESR) and positive C-reactive protein. Sample taken for bacteriology by needle aspiration were negative for sepsis from the inflammatory sites. Skull radiograph did not yield any abnormal findings (expected in myeloma). Sonography of thyroid and parathyroids ruled out any lesions like thyroid primary or parathyroid hyperplasia or adenoma. Tuberculin test (Mantoux skin test) widely used for detection of tuberculous infection was negative. Therefore, possibility narrowed down to bone secondary with unknown primary.
Bone metastasis necessitated evaluation for prostate, lung, renal and thyroid primary. Abdominal sonography was done to rule out primary in abdomen and to look for possible secondaries in liver. Abdominal sonography readily revealed right-sided renal mass with loco-regional spread. Urine routine microscopy showed few pus cells and RBCs. Therefore primary renal tumor was provisionally diagnosed. Guided needle biopsy subsequently confirmed the renal mass as to be clear cell type of renal cell carcinoma.
Urinary BenceJone's protein and serum Electrophoresis for M band were negative for myeloma. Biphosphonate (Osteofos) and nasal calcitonin spray (Calcinase) was started from the next day that provided good pain control within a couple of days. Needle biopsy from the lytic lesions taken later suggested metastatic disease of renal origin. Unfortunately, the patient refused any further treatment or intervention except medications for pain relief, after knowing that he is suffering from a malignant disease despite adequate counselling regarding potential treatment options.