Role of skeletal scintigraphy in advanced retinoblastomas

To document the incidence of skeletal metastases exclusively in advanced cases of retinoblastoma and to rationalize the use of preoperative skeletal scintigraphy in such patients.

Preoperative bone scans of 36 consecutive patients with advanced retinoblastoma who underwent skeletal scintigraphy during 1998 to 2003 were analyzed retrospectively. Bone scans were classified as: Grade 1 (high probability scan for skeletal metastases), Grade 2 (equivocal malignant or benign abnormalities), or Grade 3 (normal or certainly benign lesions).

Grade 1 scan was found in 3 (8.33%) patients; bone metastases were confirmed by additional investigations. Grade 2 scan was found in 5 (13.88%) patients; bone metastases were excluded in all by additional investigations. Grade 3 scan was found in the remaining 28 (77.77%) patients. Extraorbital extension of disease was demonstrated by fine needle aspiration of lymph nodes in five patients, which included all three patients with Grade 1 scan. In addition to lymph node metastases, two patients had intracranial extension of the disease; demonstrated by contrast-enhanced magnetic resonance imaging of the head. One patient had liver metastases detected on abdominal ultrasound. None of the patients had skeletal metastases only.

Routine preoperative bone scan is not justified in patients with locally advanced retinoblastoma. Bone scan should only be performed in patients with documented extraocular metastatic disease.