Lessons From the Friday Unknowns The patient is a 67-year-old man with autoimmune hemolytic anemia associated with cold agglutinins. Peripheral blood: WBC: 4.2 K/uL, Hgb 8.5 g/dL, MCV 96.8 fL, Platelet 248 K/uL Mild normocytic, normochromic anemia with red cell agglutinates, normal leukocyte count with rare atypical lymphocytes and no circulating blasts, normal platelet count…

Lessons From the Friday Unknowns Histologic sections show needle-shaped fragments of lymphoma with large areas of necrosis. The neoplasm has a diffuse pattern and a prominent starry sky appearance. The neoplastic cells are intermediate-size and there are many apoptotic cells. Residual breast ducts are also present surrounded by the neoplasm.

Lessons From the Friday Unknowns The H&E slides show lymph node with follicular pattern in a partially preserved architecture. The neoplastic follicles are composed of centroblasts but not centrocytes, and there is a loss of mantle zones. The centroblasts display irregular nuclei, dispersed chromatin, and distinct nucleoli. No definitive centrocytes are identified. …

Lessons From the Friday Unknowns The lymphoma has a predominantly nodular pattern, with some areas appearing to show a diffuse pattern without recognizable nodularity. Lymphoma cells are of intermediate to large size. Mitotic division figures are moderately numerous.

Lessons From the Friday Unknowns The patient is an 18 years old man with neck lymphadenopathy. Histologic sections of the left neck biopsy specimen show extensive involvement by lymphoma. One small area in the specimen appears to represent residual lymph node. The neoplasm has a diffuse pattern and a prominent starry sky appearance. The neoplastic…

Lessons From the Friday Unknowns Histologic sections show lymphoma involving adipose tissue. No evidence of lymph node is identified. The neoplasm has two components. There is a prominent plasmacytic component between follicles and there is a smaller lymphoid component with a partial marginal zone distribution. The neoplastic plasma cells are generally small without marked atypia…

Lessons From the Friday Unknowns Histologic sections show fragments of salivary gland involved by lymphoma. The lymphoma cells are monotonous and small to intermediate-size with open to stippled chromatin with usually one nucleolus (blastoid appearance). Numerous mitotic figures and apoptotic bodies are present. Surrounding adipose tissue is also involved by the lymphoma. The lymphoma cells…

Lessons From the Friday Unknowns Histologic sections demonstrate two processes: One process affects lymphoid tissue and shows characteristic features of hyaline vascular type of Castleman disease. Specifically, lymphoid follicles are markedly increased and scattered throughout the cortex and medulla. Some follicles contain two or more small germinal centers (so-called “twinning”). Many germinal centers are depleted…