Case of the Month: January 2022
posted: January 18, 2022
This is a 62-year-old patient with over 2-year history of right facial swelling. MRI shows an isolated T2 hyper intense masticator space mass with post contrast enhancement. No masses or lymphadenopathy are noted elsewhere. Autoimmune work up is negative. An excisional biopsy is performed and submitted for histopathological evaluation.
The provided tissue shows lymphoid rich lesion with variably sized secondary follicles, atrophic and sclerotic germinal centers, vague mantle zone proliferation and onion skinning. Interfollicular benign vascular proliferation is prominent. Additionally, there is noticeable follicular dendritic cell proliferation confined to the follicles and displays occasional atypia. Plasma cells are inconspicuous. Thorough phenotypic analysis is applied to exclude B- and T-cell lymphoma by flow cytometry and immunostaining. No aberrant B- or T-cells are identified. B-cells are polytypic by flow cytometry. CD21, CD35 and CD23 highlight prominent follicular dendritic cell meshwork including occasional multinucleated/dysplastic forms. Viral infection work up including HHV8 immunostain, CMV immunostain and EBV by in-situ hybridization are negative.
Final Diagnosis: Castleman Disease, Unicentric, Hyaline Vascular Variant
Castleman disease is a lymphoproliferative disorder that histologically can have different variants with overlapping pathological features and different clinical outcomes including unicentric, multicentric and HHV8-positive variant. In general, clinical correlation and extensive laboratory workup are required to reach a definitive clinical diagnosis and to exclude mimickers such as infection, autoimmune disease, IgG4 disease and certain lymphomas. After thorough and necessary work up, an infectious, autoimmune etiology, and lymphoma were confidently excluded in this case. Given the isolated nature of this lesion and the overall morphology, the diagnosis is Castleman disease, unicentric, hyaline vascular variant that is managed by complete excision only. Follicular dendritic cell dysplasia can occasionally be seen associated with this entity and careful examination of the entire tissue is necessary to exclude Follicular dendritic cell sarcoma.
Wu D, Lim MS, Jaffe ES. Pathology of Castleman Disease. Hematol Oncol Clin North Am. 2018 Feb;32(1):37-52. PMID: 29157618
Case contributed by Dr. Saja Asakrah MD,PhD (Emory University Hospital, Department of Pathology)