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Selected Heritable Skin Diseases of Domesticated Animals
Published in John P. Sundberg, Handbook of Mouse Mutations with Skin and Hair Abnormalities, 2020
Robert W. Dunstan, Robert A. Kennis
Clinical features — Bernese Mountain dogs appear uniquely sensitive to developing lethal, systemic, histiocytic, proliferative diseases. Two forms have been recognized: systemic histiocytosis and malignant histiocytosis. Although these forms most reasonably represent different spectra of the same disease process, definition of a continuum has yet to be described.
Unexplained Fever In Hematologic Disorders
Published in Benedict Isaac, Serge Kernbaum, Michael Burke, Unexplained Fever, 2019
High fever is common to all forms of histiocytosis. In malignant histiocytosis it is believed to be a constant characteristic and its absence makes the diagnosis unlikely.140 Other common features in both the malignant and the benign reactive disorders are the presence of constitutional symptoms and organomegaly. The overlapping clinical characteristics among disorders of such diverse etiologies may be explained by similarities in behavior of the activated macrophages in both benign and malignant disorders, notably hemophagocytosis, osteolysis, tissue invasion, and release of endogenous pyrogens.133
Lymph Node
Published in Joseph Kovi, Hung Dinh Duong, Frozen Section In Surgical Pathology: An Atlas, 2019
Joseph Kovi, M.D. Hung Dinh Duong
The following pathologic entities must be considered in the differential diagnosis: metastatic carcinoma (melanoma), and malignant histiocytosis. Sinus histiocytes are relatively large cells with abundant, pale pink or vacuolated cytoplasm and small round or ovoid nuclei without distinct nucleoli. The nucleo-cytoplasmic ratio in metastatic carcinoma (melanoma) cells is high. The neoplastic cells exhibit prominent nucleoli. The cytoplasm of the neoplastic cells is usually basophilic (blue) because of the rich cytoplasmic ribosome content. Malignant histiocytosis is a very rare disorder. Malignant histiocytes exhibit considerable nuclear atypia, pleomorphism, and marked erythrophagocytosis.
Histiocytic sarcoma arising in a child affected by Burkitt lymphoma, with t(8;14)(q24;q32) positivity in both tumors
Published in Pediatric Hematology and Oncology, 2021
Emanuele S.G d’Amore, Chiara Mainardi, Lara Mussolin, Elisa Carraro, Rita Alaggio, Elena Lazzari, Stefano Fusetti, Cristina Ghirotto, Antonio Marzollo, Giada Biddeci, Tiziana Toffolutti, Davide Massano, Giovanni Scarzello, Monica Zuliani, Maria Caterina Putti, Alessandra Biffi, Marta Pillon
Histological diagnosis of MH-HS is challenging. According to the WHO 2017 classification, histiocytic neoplasms are derived from mononuclear phagocytes (macrophages and dendritic cells) or histiocytes and comprise several different entities; MH-HS represent a subgroup of these tumors showing morphological and immunophenotypic features of mature tissue histiocytes.2 MH-HS can arise at any site, as a primary (de novo) or secondary neoplasm, and may be localized or disseminated at diagnosis. No clear prognostic factors have been identified. A disseminated onset has been more often reported, and the neoplasm, especially if secondary, usually has an aggressive course, requiring an intensive therapeutic approach resembling the one used for lymphomas. However it is difficult to ascertain the real incidence of these rare tumors in the pediatric age as many cases previously classified as malignant histiocytic sarcomas or malignant histiocytosis are actually T-cell neoplasms.13
Short-term response to alemtuzumab in CD52-positive secondary histiocytic sarcoma in a child: Is it time to consider new targets?
Published in Pediatric Hematology and Oncology, 2020
Elvis Terci Valera, María Sol Brassesco, Maristella Bergamo Francisco dos Reis, Gilberto Maggioni, Renato Luiz Guerino-Cunha, Carlos Eduardo Grecco, Jorge Elias Jr., Mery Kato, Luiz Gonzaga Tone
Histiocytic and macrophage-dendritic neoplasms are very uncommon tumors with variable clinical behavior. Current classification proposal stratifies these lesions into five main groups: L (Langerhans), C (Cutaneous and mucocutaneous histiocytosis), R (Rosai-Dorfman Disease and miscellaneous noncutaneous, non-Langerhans cell histiocytosis), M (Malignant histiocytosis) and H (Hemophagocytic lymphohistiocytosis and macrophage activation syndrome).2 A large spectrum of histiocytic lesions has been described in association with leukemia in children.3 These lesions range from benign, locally aggressive, to highly malignant tumors. HS is a subtype of malignant histiocytosis considered a very aggressive and potentially lethal end of this spectrum where genetic information and new insights supporting precision therapies are warranted. Owing to the paucity of clinical and genetic information on pediatric cases of secondary HS following ALL, our brief report aimed to add a thorough description on both clinical and genetic findings of this association in a child. Clinical experience with targeted-therapy as a rescue regimen using alemtuzumab is also described. In addition, we proposed to gather and to explore the most frequent mutations and leading cell pathways involved in this SMN described in pediatric cases to date.
A chronic eyelid lesion in a child: multi-disciplinary approach to diagnosis, treatment and management of a highly atypical histiocytic lesion
Published in Pediatric Hematology and Oncology, 2022
Archana Ramgopal, Julia Segal, Sabrina Mukhtar, Jenny Yu, Jennifer Picarsic, Jean M. Tersak, Steven W. Allen
Given the rarity of HS, the published literature is limited to only a few review articles, case reports, and case series. In the pediatric population, reports are even scarcer, with most occurring after a prior leukemia. Clinically, this patient’s lesion appeared localized and low-grade, and the patient underwent a superficial excision prior to pathology findings. Diagnosis in the current case was difficult as pathology was initially concerning for a high-grade histiocytic lesion with a xanthogranuloma immunophenotype given the atypical findings including monomorphic proliferation with very high Ki-67, increased mitoses, and lack of Factor XIIIa expression. In the literature, Koren et al. describe a highly mitotically active deep JXG, with Ki-67 positivity found to be only 15%, in contrast to the > 50% Ki-67 positivity seen in our patient’s lesion. 9 There is little guidance in the literature for treatment of atypical appearing histiocytic lesions that span features from low-grade to high-grade histiocytic neoplasms. One such case with an elevated Ki-67 in an otherwise low-grade appearing xanthogranuloma lesion in a child was found to have a BRAF fusion and clinically aggressive features.4 In our case, a PET scan was conducted after resection of the eyelid lesion, although it was unknown whether the original resected lesion was PET-avid. As pathology was not purely diagnostic of malignancy in this tumor, additional molecular testing was undertaken to discern genomic instability, and was negative without any known driver kinase alterations present using a sensitive but targeted histiocytic molecular panel.8 With the integration of the unusually high Ki-67 activity, non-lipidized appearance, lack of Touton giant cells and Factor XIIIa, but non-progressive and quiescent molecular profile, we conclude that this lesion was overall more of an atypical JXG family lesion rather than a high-grade/malignant histiocytosis. However, this and other reports, suggest that additional pathologic criteria are needed for so-called “atypical” histiocytic neoplasms that have features spanning between low- and high-grade lesions with an uncertain biologic potential.4 A minimum requirement should include the integration of sensitive molecular testing. This case highlights the importance of an integrated approach with histopathology, molecular analysis, imaging, and the multidisciplinary clinical team to arrive at a fully assimilated final diagnosis.