Castleman's disease (CD), or angiofollicular lymph node hyperplasia, creates both diagnostic and therapeutic dilemmas for most physicians. For patients with this rare and poorly understood disease, the optimal therapy is unknown. The authors report their experience during the years 1986-1997 with this uncommon clinicopathologic entity. Sixteen patients with a histologic diagnosis of CD were identified in the pathology database. Unicentric disease was defined as a solitary mass. Multicentric disease compromised patients with widespread lymphadenectomy. Clinical, radiologic, and laboratory data were analyzed to evaluate treatment response. The study group consisted of 16 patients classified into 3 clinicopathologic groups: hyaline-vascular, plasma cell, and "mixed." Of those patients who underwent complete surgical excision of a unicentric hyaline-vascular CD mass (n = 8), all remain symptom free without clinical or radiographic recurrence. Two patients remain asymptomatic following partial resection or radiation therapy for an unresectable unicentric hyaline-vascular CD mass. Two patients with multicentric hyaline-vascular CD are currently in complete remission following adjuvant therapy. Multicentric plasma cell CD was present in a single patient. This patient (who underwent surgical and systemic therapy) died of disease within 4 months of presentation. Three patients with unicentric hyaline-vascular/plasma cell-CD remain symptom free following either complete resection or observation. The authors recommend surgical resection for patients with the unicentric variant of CD. Surgical removal of a unicentric mass of hyaline-vascular or hyaline-vascular/plasma cell type is curative. Partial resection, radiotherapy, or observation alone may avoid the need for excessively aggressive therapy. Patients with multicentric disease, either hyaline-vascular or plasma cell type, do not benefit from surgical management and should be candidates for multimodality therapy, the nature of which has yet to be defined.