{'fraction_non_alphanumeric': 0.03605891315388522, 'fraction_numerical': 0.021838496698831894, 'mean_word_length': 5.700680272108843, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Malignant histiocytosis a reassessment of cases previously reported in 1975 based on paraffin section immunophenotyping studies

Malignant histiocytosis (MH) is a term that has been used to describe a syndrome in which there is a systemic proliferation of cells that have the cytologic appearance of atypical histiocytes. Biopsy materials from 15 patients with malignant lymphoma diagnosed as malignant histiocytosis in a previous study reported in 1975 were analyzed by a panel of antibodies and reclassified using current nosologic concepts of malignant lymphoma. The antibodies used comprised reagents detecting a formalin‐resistant epitope on B‐cells (L26), T‐cells (anti‐CD3, anti‐leu 22 [CD43], and UCHL1 [CD45RO]), monocyte/macrophage‐derived cells (KP1 [CD68]), as well as antibodies that detect leukocyte common antigen (PD7 [CD45RB]), and a formalin‐resistant epitope of Ki‐1 (Ber‐H2 [CD30]). The authors found that nine lymphomas had a profile consistent with T‐lineage, including six in which Ki‐1 (CD30) was coexpressed, and two were B‐lineage. Three lymphomas showed no specific lineage characteristics although two were Ki‐1 (CD30) positive, and none had expression of KP1 (CD68). The 12 lymph node biopsy specimens showed a variety of patterns of involvement, including sinusoidal, paracortical, and diffuse; the spleens showed predominantly red pulp involvement. A 15th case was believed most consistent with a virus‐associated hemophagocytic syndrome. These findings support previous suggestions that the majority of cases diagnosed as MH represent T‐lineage‐associated hematolymphoid neoplasms, and that only a rare case will be of monocyte/macrophage origin. It is suggested that the term MH be subsumed under the rubric of large cell lymphoma and unless there are compelling immunohistochemical data to support a histiocytic origin, that the term MH be abandoned in favor of a more accurate descriptive term, such as sinusoidal large cell lymphoma.