Metastatic adenocarcinoma presenting as monoarticular arthritis of the knee: A case report with review of literature.

Patients who develop metastatic arthritis secondary to solid tumors are rare. It is even more uncommon to be a presenting symptom. We present a case where a known case of osteoarthritic patient presented with complaints of knee swelling secondary to primary colonic carcinoma with lung metastasis. It was initially diagnosed on histopathology examination as metastatic adenocarcinoma from excised synovial mass and further investigated for primary carcinoma. Later, computed tomography was done and found out the primary colonic carcinoma arising from transverse colon along with lung metastasis.