cow-2023-02

a. IgG4 related disease
b. Lymphoplasmacytic lymphoma
c. Plasma cell neoplasm
d. Urothelial carcinoma, plasmacytoid variant
e. Reactive plasmacytosis

1. c

Plasma cell neoplasm, muscularis propria present and involved

Sections show an infiltrative neoplasm composed of sheets of large, atypical plasmacytoid cells with uniform eccentric nuclei, abundant eosinophilic cytoplasm and variably prominent nucleoli. Mitotic figures are frequent. Overlying urothelial epithelium is unremarkable. Muscularis propria is present and involved by the infiltrate. Tumor cells are strongly positive for CD138. Ki67 shows a >90% proliferative index. GATA3 highlights the uninvolved benign surface urothelium, tumor cells are negative.

Urothelial carcinoma, plasmacytoid variant will have areas of classic urothelial carcinoma. Lymphoplasmacytic lymphoma will be CD20+ with kappa/lambda restriction and variable CD138 positivity. Reactive plasmacytosis and IgG4 related disease will not have overt atypia, as seen in this case.

Solitary bladder plasmacytoma, a type of extramedullary plasmacytoma, is very rare. Multiple myeloma is a common hematological disease characterized by the proliferation of clonal plasma cells and the production of monoclonal proteins. Most solitary extramedullary plasmacytomas are seen in the head and neck and the upper respiratory tract. The second most frequent site is the gastrointestinal tract. Few rare sites reported include the central nervous system, thyroid, breast, testes, parotid glands, and urinary bladder. Bladder plasmacytoma is extremely uncommon, with only a handful of cases reported, of which majority of them had a clinical diagnosis of multiple myeloma.

Radiation is the main treatment of solitary bladder plasmacytoma. Sometimes, radiation combined surgery may be better than radiation alone. Close monitoring and follow-up are important as well. Monoclonal protein is a significant laboratory examination for the prognosis of this disease.

Cormio L, Mancini V, Calò B, Selvaggio O, Mazzilli T, Sanguedolce F, Carrieri G. Asymptomatic solitary bladder plasmocytoma: A case report and literature review. Medicine (Baltimore) . 2017;96:e9347.

Wadhwa K, Singh R, Solomon LZ. Bladder extramedullary plasmacytoma and synchronous bladder urothelial transitional cell carcinoma: A case report and review of the literature. Open Access J Urol . 2011;3:25–27.

Safee Ahmed MD, Washington University in St. Louis, a.safee@wustl.edu, @SafeeAhmedGU
Nidia Messias MD, Washington University in St. Louis, m.nidia@wustl.edu, @MessiasNidia

Bladder

Bladder mass, plasma cell neoplasm