Final Diagnosis -- Follicular Dendritic Cell Tumor (Right Neck Mass)

FINAL DIAGNOSIS:

Right Thyroid and Right Cervical Lymph Node:

Follicular Dendritic Cell Tumor

Contributor's Note:
This is a recently recognized rare tumor that has been reported as reticulum cell sarcoma, sarcoma of follicular dendritic cells, among others. It is a tumor arising in the follicular dendritic cells of lymph nodes. The reticulum cells in lymphoid tissue may differentiate along a few lines - histiocytic, fibroblastic or dendritic/interdigitating. Dendritic and interdigitating cells are antigen processing cells that express CD1, CD21 and variably CD68 and S-100 protein. In the studies reported thus far, patients have been treated with a variety of modalities, including chemotherapy, radiation and/or surgery.

References:

1. Weiss LM, Berry GJ, Dorfman RF, Banks P, Kaiserling E, Curtis J, Rosai J, Warnke RA. Spindle cell neoplasms of lymph nodes of probable reticulum cell lineage: true reticulum cell sarcoma? Am J Surg Pathol 1990, 14 (5): 405-414.
   
2. Chan JKC, Tsang WYW, Ng CS. Follicular dendritic cell tumors of the oral cavity. Am J Surg Pathol 1994, 18(2):148-157.
   
3. Chan JKC, Tsang WYW, Ng CS. Follicular dendritic cell tumor and vascular neoplasm complicating hyaline-vascular Castleman's disease. Am J Surg Pathol 1994, 18(5):517-525.

Contributed by Jeff Nine, M.D., Leon Barnes, M.D. and Steven Swerdlow, M.D.