Follicular lymphoma with a predominantly diffuse growth pattern with 1p36 deletion: a clinicopathologic analysis of eight cases / 中华病理学杂志

Objective: To investigate the clinical and pathologic features and diagnosis of follicular lymphoma (FL) with a predominantly diffuse growth pattern (DFL) with 1p36 deletion. Methods: Eight cases of DFL with 1p36 deletion diagnosed at Department of Pathology, Beijing Friendship Hospital, Capital Medical University (n=5) and the Affiliated Cancer Hospital of Zhengzhou University, Henan Cancer Hospital (n=3) from January 2017 to January 2023 were included. Their clinicopathologic features and follow-up data were analyzed. Immunohistochemistry and fluorescence in situ hybridization (FISH) were performed. Results: There were five males and three females, with a median age of 67 years, and inguinal lymphadenopathy was found as the main symptom. Histologically, similar morphologic features were sheared among all cases, with effaced nodal structure and characterized by proliferation of centrocytes in a diffuse pattern, with or without follicular components. The germinal center-related markers such as CD10 and/or bcl-6 were expressed in the tumor cells, and 1p36 deletion but not bcl-2 translocation was appreciable in these cases. Conclusions: DFL with 1p36 deletion is a rare subtype of FL, with some overlaps with other types of FL or indolent B-cell lymphomas in their pathologic features. An accurate diagnosis requires comprehensive considerations based on their clinical, pathologic, immunohistochemical, and molecular features.

Clinicopathological study of epithelioid and spindle cell rhabdomysarcoma with EWSR1/FUS-TFCP2 fusion / 中华病理学杂志

Objective: To investigate the clinicopathological and genetic features of epithelioid and spindle cell rhabdomysarcoma with EWSR1-TFCP2 or FUS-TFCP2 fusion. Methods: The clinical, morphological and immunohistochemical features of 14 cases of epithelioid and spindle cell rhabdomysarcoma with EWSR1-TFCP2 or FUS-TFCP2 fusion diagnosed from January 2019 to December 2022 in the Department of Pathology, Foshan Traditional Chinese Medicine Hospital, Foshan, China were retrospectively analyzed. The cases were all subject to FISH or next generation sequencing for analysis of molecular genetic features. The literature was reviewed. Results: There were 5 males and 9 females, with the age at presentation ranging from 6 to 36 years (mean, 22 years). Tumors occurred in the head and neck (9 cases), pelvic region (2 cases), bladder (one case), right humerus (one case), and the abdominal wall, humerus and pubic at the same time (one case). Presenting symptoms varied by location but often included pain or discomfort. Most of the patients showed aggressive radiographic features with soft tissue extension. The tumors had a median size of 6.6 cm (range, 2-23 cm). The tumors were poorly defined and irregularly shaped. Microscopic examination showed diffuse proliferation of spindle or epithelioid cells. While morphologically high-grade tumors displayed obvious cytological atypia, a high mitotic count and tumor necrosis, low-grade tumors grew in sheets and fascicles composed of spindle, epithelioid cells with moderate or abundant amounts of eosinophilic cytoplasm, without pronounced cytological atypia. The tumor cells expressed Desmin, MyoD1, and Myogenin, as well as ALK, EMA, and CKpan. EWSR1/FUS-TFCP2 gene fusion was detected in 14 cases with next generation sequencing and confirmed by FISH. Six cases had EWSR1-TFCP2 fusions and 8 cases showed FUS-TFCP2 fusions. Follow-up information was available in 13 patients, ranged from 5 to 37 months. At the end of follow-up period, 7 patients died of the disease. Six patients were alive:two cases had local recurrences and metastases, two cases of recurrences, one case of metastasis and one case without recurrences and metastasis. Conclusions: Epithelioid and spindle cell rhabdomysarcomas with EWSR1-TFCP2 or FUS-TFCP2 fusion show a very aggressive clinical course, and more commonly occur in the head and neck. Their genetic hallmark is the presence of EWSR1/FUS-TFCP2 fusions. Familiarity with its clinicopathological characteristics is helpful in avoiding misdiagnoses.

Progressively transformed germinal center-like follicular T-cell lymphoma:a clinicopathological analysis of 14 cases / 中华病理学杂志

Objective: To investigate the clinicopathologic features of progressively transformed germinal center-like follicular T-cell lymphoma (PTGC-like FTCL). Methods: The clinicopathologic data of 14 PTGC-like FTCL cases that were diagnosed at the Beijing Friendship Hospital Affiliated to the Capital Medical University from January 2017 to January 2022 were retrospectively collected. Clinicopathological features, immunophenotype, and Epstein-Barr virus (EBV) infection status were analyzed in these cases. Polymerase chain reaction (PCR) was performed to detect the clonal gene rearrangements of T cell receptor (TCR) and the immunoglobulin (Ig) in 10 and 8 cases, respectively. Results: The male to female ratio was 5∶2. The median age was 61 years (range 32-70 years). All patients had lymphadenopathy at the time of diagnosis. By using the Ann Arbor system staging, seven cases were classified as stage Ⅰ-Ⅱ, and seven cases as stage Ⅲ-Ⅳ. Seven cases had B symptoms, four cases had splenomegaly, and two cases had skin rash and pruritus. Previously, three cases were diagnosed as classic Hodgkin's lymphoma, three cases as small B-cell lymphoma, two cases as atypical lymphoid hyperplasia unable to exclude angioimmunoblastic T-cell lymphoma (AITL), one case as EBV-associated lymphoproliferative disorder, and one case as peripheral T-cell lymphoma (PTCL) associated with the proliferation of B cells. All the 14 cases showed that the large nodules were composed of mature CD20+, IgD+B lymphocytes admixed with small aggregates of neoplastic cells with pale to clear cytoplasm. Moreover, hyperplastic germinal centers (GCs) and Hodgkin/Reed-Sternberg-like (HRS-like) cells were seen within these nodules in two and five cases, respectively. The neoplastic cells expressed CD3 (14/14), CD4 (14/14), PD1 (14/14), ICOS (14/14), CD10 (9/14), bcl-6 (12/14), CXCL13 (10/14), and CD30 (10/14). The HRS-like cells in five cases expressed CD20 (2/5), PAX5 (5/5), CD30 (5/5), CD15 (2/5), LCA (0/5), OCT2 (5/5) and BOB1 (2/5). Moreover, neoplastic T cells formed rosettes around HRS-like cells. EBV-encoded RNA (EBER) in situ hybridization showed scattered, small, positive bystander B lymphocytes in 8/14 cases, including 3/5 cases containing HRS-like cells. All tested cases (including five with HRS-like cells) showed monoclonal TCR gene rearrangement and polyclonal Ig gene rearrangement. Conclusions: PTGC-like FTCL is a rare tumor originated from T-follicular helper cells. It could be distinguished from angioimmunoblastic T-cell lymphoma by the formation of follicular structure, and lack of follicular dendritic cell proliferation outside the follicles and the polymorphous inflammatory background. In addition, it should be differentiated from lymphocyte-rich classical Hodgkin's lymphoma and low-grade B cell lymphoma.