March 2002: 28-year-old woman with neck and back pain

Following a car accident a 28-year-old female, complained of a sharp pain of the anterior and posterior base of the neck on expiration and with exertion. Subsequently, she noticed a feeling of discomfort in her back when lifting her arm above her head. Imaging studies revealed a tumor mass involving the third intercostal nerve on the right side of T2. The differential diagnosis included neurofibroma and neurilemmoma. This was followed annually and five years later an increase in size warranted a transthoracic, transpleural removal en bloc of this lesion. At surgery, a 3 cm soft tissue tumor engulfed the third intercostal nerve and extended into the third intervertebral foramen where the proximal part of the nerve root was enlarged. The right third intercostal nerve was dissected and removed along with the tumor, after negative nerve stimulation. Histopathological examination showed multiple enlarged coalescent lymphoid follicles with an onion skin appearance of tight concentric layering of small, uniform mature lymphocytes at the periphery, arranged in a targetoid fashion with broad mantle zones and relatively small germinal centers. The germinal centers of variable size included hyalinized blood vessels. Lollipop follicles were seen. The interfollicular stroma showed numerous hyperplastic collagenized capillaries within an inflammatory background. However, the perinodal soft tissue was replaced by numerous inflammatory cells, primarily lymphocytes. The final diagnosis was Castleman's disease, hyaline vascular type. Castleman's disease can mimic various tumors and because Castleman's disease is a rare reactive entity, its diagnosis is generally overlooked by radiologists and clinicians. It is likely that this mass arose from one of the posterior intercostal lymph nodes, situated in the paravertebral region, however the capsule was not readily seen and the sinuses were not apparent. Almost all previous cases of Castleman's disease, hyaline vascular type were described in the anterior mediastinum. Hyaline vascular Castleman's disease usually does not invade and replace neighboring structures. This case is unique because of its location and the local invasion of adjacent structures.