Diffuse large B-cell lymphoma with Homer-Wright rosettes, sinusoidal growth pattern, and CD30 expression: a possible overlap between microvillous lymphomas and sinusoidal CD30-positive large B-cell lymphomas

Rosette-forming multicentric B-cell lymphoma in a giant panda

Literature covering diseases of the giant panda (Ailuropoda melanoleuca) is either in Chinese or focuses on infectious agents. Here we describe the clinical signs, gross and microscopic findings, and immunohistochemistry results of a B-cell lymphoma in multiple organs of a 35-y-old captive male giant panda. The animal was euthanized because of prolonged anorexia and vomiting. Postmortem examination revealed ascites, generalized lymphadenopathy, splenomegaly, hepatomegaly, and thickened gall bladder mucosa. Histologically, the architecture of these organs was effaced by a densely cellular neoplasm composed of large, CD79a-positive neoplastic B lymphocytes supported by a fine fibrovascular stroma. Neoplastic cells occasionally palisaded around an eosinophilic fibrillary center, sometimes resembling Homer Wright rosettes. To our knowledge, rosette-forming lymphoma has not been reported previously in animals.

Diffuse Large B-Cell Lymphoma with pseudo Rosettes, A Rare Entity: Case Report with Literature Review

Background: Rosette formation is an unusual finding in malignant lymphomas. We report a case of a diffuse large B-cell lymphoma (DLBCL) with abundant rosette formation histologically mimicking non lymphoid tumors. Case presentation: A sixty-five-year-old female presented with a complaint of swelling on left side axillary region since a period of six months with no history of fever, fatigue or weight loss or other similar swellings elsewhere. No relevant personal and family history relatable to the present complaint. Subsequent clinical and radiological investigations revealed isolated left axillary lymphadenopathy. The lymph node on further biopsy showed a particular morphology of pseudorosette formation masquerading a metastatic rosette forming malignancies. Subsequent histopathological and immunohistochemical investigations revealed a rare morphological variant of diffuse large B cell lymphoma. The fluorodeoxyglucose positron emission tomography scan showed multiple discreet supra-diphramatic (left lower cervical and left axillary lymph nodes) metabolically active lymph nodes. Conclusion: Diffuse large B cell lymphoma with rosette formation is a rare entity which can mimic other tumors with rosette formation in a metastatic node. Knowledge on the rosette forming lymphoma entity is thus essential for diagnosis and treatment plan. To the best of our knowledge this case report is the sixth known documented case of a diffuse large B cell lymphoma with rosette in literature.

The clinicopathological and molecular features of sinusoidal large B-cell lymphoma

We report 17 cases of sinusoidal large B-cell lymphoma (SLBCL). Clinical, morphologic, immunophenotypic, and molecular features were detected and analyzed. All cases showed an obvious sinusoidal growth pattern, usually associated with residual atrophic lymphoid tissue. All tumors contained large pleomorphic lymphoid cells and one or more prominent nucleoli, with abundant amphophilic cytoplasms; 15/17 cases showed anaplastic morphologic features. The patient age ranged from 43 to 80 years (median 57 years), and 7 males and 10 females were included. Eleven of 15 (73.3%) patients had Ann Arbor stage III or IV disease, and 10/15 (66.6%) patients had an International Prognostic Index (IPI) score ≥3. Immunophenotypically, 16/17 (94.1%) cases displayed a nongerminal center B-cell (non-GCB) immunophenotype. Furthermore, 16/17 (94.1%) cases were positive for CD30, and p53 was expressed in 10/16 (62.5%) cases. In total, 12/14 (85.7%) cases expressed BCL2 and MYC simultaneously (double expression), and 11/14 (78.6%) cases showed PD-L1 positivity (6/11 had a PD-L1 tumor proportion score ≥50%). Cytogenetically, concurrent MYC and BCL2 and/or BCL6 abnormalities (break-apart or extra copy) were detected in 10/15 cases, and 7/13 (53.8%) cases harbored a PD-L1/L2 amplification. TP53 mutation was found in 7/13 (53.8%) cases by Sanger sequencing. Whole-exome and large-panel sequencing results revealed high mutation frequencies of TP53 (4/7), MYD88 (3/7), KMT2D (3/7), CREBBP (3/7), and PIM1 (3/7). Among the 13 patients with SLBCL treated with aggressive chemotherapy regimens, the median overall survival (OS) was 18 months, and the 2-year OS rate was 34.6%. The OS of patients with SLBCL was markedly worse than that of 35 control group patients with common diffuse large B-cell lymphoma (DLBCL) without sinusoidal features (P < 0.001). SLBCL may represent a specific type of DLBCL that has characteristic pathologic features. The cancer is aggressive in most clinical cases, and outcomes are poor. SLBCL and anaplastic DLBCL (A-DLBCL) have many overlapping clinicopathological and molecular features.

CD30-Positive Anaplastic Variant of Diffuse Large B-cell Lymphoma: Frequency and Association With Clinicopathological Parameters

Introduction

Diffuse large B-cell lymphoma (DLBCL) is an aggressive B-cell lymphoma and is the most common type of non-Hodgkin's lymphoma (NHL) worldwide. The World Health Organization (WHO) classification of hematopoietic tumors has recognized three morphological variants of DLBCL: centroblastic, immunoblastic, and anaplastic. Some studies have shown that the anaplastic variant of DLBCL is associated with aggressive clinicopathological features. Anaplastic DLBCL is rare, and the clinicopathological characteristics of this subtype of DLBCL are not widely studied in our population. Therefore, in this study, we evaluated the frequency of the anaplastic variant of DLBCL and its association with other clinicopathological parameters.

Methods

A retrospective study was conducted in the Department of Histopathology at the Liaquat National Hospital and Medical College over a period of six years, from January 2015 to December 2020. All cases diagnosed as DLBCL based on morphology and immunohistochemical (IHC) profile were included in the study. The diagnosis of anaplastic DLBCL was rendered based on morphology (large bizarre pleomorphic cells in a cohesive or sheet-like growth pattern), combined with CD30 IHC expression.

Results

The mean age of the patients was 52.90 ±16.42 years, and the mean Ki67 index was 73.18 ±16.52%. Of the 220 cases of DLBCL, 47.3% cases were germinal center B-cell (GCB) subtype, and 59.1% cases were nodal. BCL-2, BCL-6, MUM1, c-MYC, and CD10 positivity were noted in 60%, 45.5%, 40.9%, 44.1, and 38.6% cases, respectively. Only 14 cases (6.4%) were recognized as anaplastic variants of DLBCL according to the previously defined criterion. The only significant association of anaplastic-variant DLBCL was noted with a lack of BCL-2 expression. No significant association of anaplastic-variant DLBCL was noted with age, gender, Ki67 index, DLBCL subtype, or any other IHC marker expression.

Conclusion

We found a low frequency of the anaplastic variant of DLBCL in our study. No significant association of this DLBCL variant was noted with any of the clinicopathological parameters, except for the lack of BCL-2 expression. Alternatively, from a pathological perspective, it is important to recognize this variant of DLBCL as it often mimics other CD30-positive lymphoma and undifferentiated carcinoma.

CD30-positive anaplastic variant diffuse large B cell lymphoma: a rare case presented with cutaneous involvement

A 67-year-old man suffered from a left cervical lymph node swelling and tenderness. Biopsy of the cervical lymph node showed pleomorphic large cells containing large atypical nuclei. Immunohistochemical stains of these cells were positive for CD30, but negative for CD3 and CD20. After the biopsy, his left cervical skin was ulcerated. Biopsy of the left cervical skin was performed. Large pleomorphic cells with constricted nuclei and Reed-Sternberg-like cells existed in the dermis and epidermis. Immunohistochemical stains of the former cells were positive for CD30, CD45 and PAX5, but negative for CD3, CD10, CD20, CD15, Bcl-2, EBER ISH, EMA and ALK. He was diagnosed with diffuse large B cell lymphoma, anaplastic variant. He achieved complete remission with CHOP chemotherapy. CD30-positive DLBCL, anaplastic variant is a rare B cell lymphoma. Most of the patients presented with primary nodal disease, and skin involvement of lymphoma is very rare. This is the report of a rare case of CD30-positive DLBCL, anaplastic variant, with both nodal and skin lesions.