Challenges in imaging and histopathological assessment of a giant cell tumour with secondary aneurysmal cyst in the patella

Abstract

The patella is an uncommon site for all primary and metastatic bone tumours and primary intra-osseous tumours of the patella are very rare. A majority of the patella tumours are benign. We report a patient with a sudden onset swelling and pain of the right knee following a staircase fall. The plain radiograph showed an expansile multiseptated patella lesion and it was further assessed with an MRI. The radiological findings and the initial histopathological features from a limited sample were suggestive of a primary aneurysmal bone cyst. However, the final histopathological diagnosis from a more adequate specimen was a giant cell tumour with a secondary aneurysmal bone cyst.

Giant Cell Tumor with Secondary Aneurysmal Bone Cyst of the Patella: A Case Report

“…The association of secondary ABC has been seen in 14% of GCT [1,10-13]. Although GCT and ABC are common benign tumors of the patella, a combined GCT and ABC case is extremely rare [6-9].…”

“…The clinical presentation of GCT with secondary ABC is the same as that of isolated GCT in patella [6-9]. Pain, swelling, and restriction of movement may be there in any lesion of the patella; hence, radiological and histological evaluations are crucial.…”

“…Overall the diagnosis relies on histopathology only. Again, on biopsy, if the material is aspirated from the cystic space, it may reveal hemorrhage and mislead the diagnosis or point towards ABC only [7,9]. Hence, multiple specimens from cystic as well as solid areas of tumors are essential to confirm the diagnosis from histopathology.…”

“…Hence, multiple specimens from cystic as well as solid areas of tumors are essential to confirm the diagnosis from histopathology. Low et al and Yo et al have warned that a small biopsy and limited sample may be mischievous in combined ABC and GCT [7,9].…”

“…The most common tumor is GCT (33%) followed by chondroblastoma (16%) [1,3-5]. A combined GCT and aneurysmal bone cyst (ABC) is extremely rare in the patella, and only four case reports are available in medical literature till date [6-9]. We hereby submit a case of patellar GCT with secondary ABC in a young female who presented with pain and swelling on the anterior part of the knee.…”