Sarcoid reaction in primary neuroblastoma: case report.

We present a unique case of a 9-month-old infant with a left adrenal neuroblastoma with sarcoid reaction, detected by mass screening. There was no clinical evidence indicating systemic sarcoidosis or pulmonary mycobacterial infection. Histological examination of the resected adrenal tumor revealed many noncaseating epithelioid granulomas with lymphocytic infiltrate, composed of epithelioid cells and few giant cells, arising in tumor parenchyma and fibrovascular stroma. Most of the lymphocytes in the granulomas were CD3- or CD45RO-positive T cells, with fewer being CD20-positive B cells. The lymphocytes in the epithelioid granulomas expressed CD4 or CD8, but not CD56 and CD57. CD4-positive cells were observed more within the granulomas (internal area) than in the surrounding area (external area) of the same granulomas, while most of the CD8-positive cells were seen consistently at the outer margin of the granulomas (marginal zone). CD45RA-positive T cells were observed predominantly in the external area. The results of immunostaining demonstrated that lymphocytes in granulomas of this case showed the same distribution pattern as that seen in systemic sarcoidosis. Although the sarcoid reaction is a phenomenon known to be associated with the region of cancer, granuloma within the primary neuroblastoma is extremely rare. The sarcoid reaction in the present case of neuroblastoma may be associated with a delayed-type hypersensitivity reaction, and its significance and relevance still remain obscure.