The 5th edition of the World Health Organization Classification of Haematolymphoid Tumours: Lymphoid Neoplasms.

We herein present an overview of the upcoming 5th edition of the World Health Organization Classification of Haematolymphoid Tumours focussing on lymphoid neoplasms. Myeloid and histiocytic neoplasms will be presented in a separate accompanying article. Besides listing the entities of the classification, we highlight and explain changes from the revised 4th edition. These include reorganization of entities by a hierarchical system as is adopted throughout the 5th edition of the WHO classification of tumours of all organ systems, modification of nomenclature for some entities, revision of diagnostic criteria or subtypes, deletion of certain entities, and introduction of new entities, as well as inclusion of tumour-like lesions, mesenchymal lesions specific to lymph node and spleen, and germline predisposition syndromes associated with the lymphoid neoplasms.

Histopathological Parameters of Canine Bone Marrow in Cell-Block Preparations.

Studies using the cell-block technique for bone marrow (BM) analysis are limited in the veterinary literature. This work assessed whether the histopathological analysis of canine BM was feasible using cell-block cytoinclusions prepared from fine-needle sternal aspirate samples. Eight clinically healthy young-to-middle-aged dogs underwent both fine-needle sternal aspiration for BM cell-block (BM-Cb) processing and iliac-crest BM core biopsy (BM-B). Histopathologic parameters were compared between the 2 methods. There were no statistically significant histopathological differences between hematopoietic tissue areas (P = .6294) in the BM-Cb and BM-B sections, and they had similar microscopic characteristics and microarchitecture. Cellularity and reticulin-fiber staining were equivalent in the BM-Cb and BM-B preparations in 87.5% (7/8) and 100% (8/8) of the sections, respectively. However, the quantitative results of the megakaryocytic series differed between BM-Cb and BM-B in 37.5% (3/8) of the sections, and the myeloid:erythroid (M:E) ratios differed between the 2 methods in 25% (2/8). These preliminary data indicate that cell-block preparations made from sternal fine-needle aspiration samples warrant continued evaluation in a larger number of animals, including those with various diseases affecting the bone marrow.

The sonic hedgehog signaling pathway contributes to the development of salivary gland neoplasms regardless of perineural infiltration.

The pleomorphic adenoma (PA), mucoepidermoid carcinoma (MEC), and adenoid cystic carcinoma (ACC) are common tumors arising from salivary glands whose histopathology is heterogeneous. The sonic hedgehog signaling pathway (Hh) and signal transducer and activator of transcription 3 (STAT3) play important roles in cell proliferation, favoring tumor growth. The aim of this investigation was to study components of the Hh pathway, as well as STAT3 in salivary gland neoplasms in an attempt to add information about the biological characteristics of these neoplasms. We used 9 cases of PA, 17 cases of ACC, and 20 cases of MEC. Using immunohistochemistry, SHH, GLI1, SUFU, HHIP, and STAT3 were investigated. For comparative purposes, MCM3 (cellular proliferation marker) was also included. In PA, there was high expression of cytoplasmic SHH and SUFU and low expression of STAT3 and MCM3. In the ACC, there was high expression of GLI1, HHIP, and STAT3 and low expression of SHH, SUFU, and MCM3. In the MEC, we observed high expression of SHH, GLI1, SUFU, and HHIP and low expression of STAT3 and MCM3. There was a statistically significant difference between SHH (p = 0.0064), STAT3 (p = 0.0003), and MCM3 (p = 0.0257) when all tumors were compared and a higher expression in parenchyma for all tumors when stroma and parenchyma were compared (p < 0.05). These findings suggests a possible role of Hh pathway in the development and maintenance of the cytoarchitectural pattern of PA, ACC, and MEC, as well as the participation of STAT3 in the development of ACC, irrespective perineural infiltration.

Tumor endometrioide borderline de ovário em adolescente: relato de caso / Borderline ovarian endometrioid tumor in adolescent: case report and review of the literature

Os tumores endometrioides malignos ovarianos são neoplasias epiteliais raras em pacientes jovens. Enquanto os carcinomas endometrioides ovarianos acometem mulheres na quinta e na sexta décadas de vida, os tumores borderline acometem mulheres em uma faixa etária mais ampla (de 22 a 77 anos). Descreveremos a seguir um caso raro de tumor endometrioide borderline ocorrendo em paciente de 16 anos. Desde que tumores do saco vitelino (TSV) e de Sertoli-Leydig (TCSL) podem mimetizar morfologicamente tumor endometrioide, o uso da imuno-histoquímica, além dos aspectos morfológicos, foi fundamental para estabelecer o diagnóstico diferencial entre essas condições.

Malignant endometrioid ovarian tumors are rare epithelial neoplasias among young patients. Whereas endometrioid ovarian carcinomas are more common among women in their fifth and sixth decades of life, borderline endometrioid tumors affect 22 to 77 year-old women. The present study reports a rare case of borderline endometrioid tumor in a 16 year-old patient. Since yolk sac and Sertoli-Leydig cell tumor may morphologically mimic endometrioid tumor, both the use of immunohistochemistry and morphological aspects were essential to establish the differential diagnosis.

Mesotelioma papilífero bem diferenciado do peritônio: relato de caso e revisão da literatura / Well-differentiated papillary mesothelioma of the peritoneum: case report and literature review

Mesotelioma papilífero bem diferenciado (MPBD) é um tumor incomum, geralmente assintomático, que pode ser encontrado incidentalmente no peritônio, apresentando-se como lesão nodular pequena múltipla ou solitária. Apesar de ser considerado indolente, apenas uma minoria dos casos apresenta sobrevida comprovada superior a dez anos. Relatamos um caso de uma mulher que, aos 44 anos, sem história de exposição a asbesto, apresentou sintomatologia de ascite e obstipação com tumoração em fundo de saco medindo 8,3 x 6 x 5,6cm. A biópsia do tumor revelou morfologia compatível com MPBD. Em função da impossibilidade de ressecção do tumor, a paciente foi submetida à quimioterapia. Evoluiu com sobrevida de 13 anos. O diagnóstico diferencial com tumor seroso do ovário foi estabelecido através da imuno-histoquímica (CK7+, Calretinina+, CK20-, CEA- e CD15-) e ultra-sonografia. Considerando tamanho do tumor, impossibilidade de ressecção e sintomatologia, esse caso tem sobrevida superior ao descrito na literatura.