Objective: To investigate the clinicopathologic and molecular genetic characteristics, diagnosis, differential diagnosis, treatment and prognosis of histiocyte-rich rhabdomyoblastic tumor (HRRMT). Methods: The clinical data of two cases of HRRMT diagnosed in Fujian Provincial Hospital and Fujian University of Traditional Chinese Medicine Affiliated People's Hospital from 2020 to 2021 were collected. Histopathology and immunohistochemical (IHC) staining were used to assess morphological changes; the genetic changes were analyzed with next-generation sequencing. The relevant literature was reviewed. Results: Both cases showed well-defined solid nodules and soft masses. Microscopically, the tumors had a fibrous pseudocapsule with lymphocytic aggregation, and locally invaded the surrounding skeletal muscle tissue, and the tumor cells were fusiform to epithelioid with an intensive foamy histiocytic infiltrate. No necrosis or mitosis was observed. Immunophenotyping showed the tumor cells were positive for desmin, either one or both skeletal muscle markers (myogenin or MyoD1), and negative for h-caldesmon, ALK and SMA. The Ki-67 index was<5%. Using next-generation sequencing, one case was found to harbour KRAS (G12D) and MSH3 (Q470^*) mutations. Conclusions: HRRMT is a newly described skeletal muscle tumor with uncertain malignant potential. Its diagnosis and differential diagnosis depend on morphologic and IHC staining. No specific molecular genetics changes have been identified so far.
Biomarkers, Tumor/analysis* ; Diagnosis, Differential ; Histiocytes/pathology* ; Humans ; Molecular Biology ; Muscle Neoplasms/pathology* ; Prognosis

Histiocytes/pathology* ; Humans ; Lymphoma, Extranodal NK-T-Cell/pathology* ; Nose Neoplasms/surgery*

histiocytes on histology, leading to the diagnosis of gastric xanthoma.]]>
Abdominal Pain ; Adult ; Appetite ; Child ; Deglutition Disorders ; Diagnosis ; Endoscopy ; Gastritis ; Helicobacter pylori ; Histiocytes ; Humans ; Incidental Findings ; Male ; Nausea ; Pediatrics ; Stomach Neoplasms ; Vomiting ; Xanthomatosis

Pigmented villonodular synovitis is a benign tumor arising from synovial fibroblasts or histiocytes. There are diffuse and localized forms: the former involves the entire synovium and the latter consists of nodules, small tumefactions, or pedunculated masses. The knee is the joint most commonly affected and the clinical diagnosis is difficult, so initial misdiagnosis is common. We report a case of pigmented villonodular synovitis developing in the knee of rheumatoid arthritis (RA) patient, mistaken for an RA flare-up.
Arthritis, Rheumatoid ; Diagnosis ; Diagnostic Errors ; Fibroblasts ; Histiocytes ; Humans ; Joints ; Knee ; Synovial Membrane ; Synovitis, Pigmented Villonodular

BACKGROUND: Juvenile xanthogranuloma is a benign, self-limited disorder that usually occurs in infants and young children. Xanthogranuloma is rare in adults, and therefore studies reporting adult xanthogranuloma are limited. OBJECTIVE: We investigated the clinical, histopathological, and immunohistochemical characteristics of adult xanthogranuloma. METHODS: In this study, we evaluated 20 lesions in 19 patients with adult xanthogranuloma. RESULTS: A male predominance was observed (male : female ratio 1.4 : 1), and the mean age of patients was 35.1±16.3 years (range 15∼66 years), with the peak incidence observed in patients in their 20s. Notably, 65.0% of the lesions developed on the head and neck. The nodular form was more common than the papular form of this condition. Histopathological examination revealed dense monomorphic histiocytic infiltration without lipidization and scattered eosinophils without multinuclear giant cells in 5 lesions (25.0%), foamy histiocytic infiltration with variations of completely developed Touton giant cells in 10 lesions (50.0%), and fibrohistiocytic proliferation in 3 lesions (15.0%). On immunohistochemical examination, histiocytes including giant cells showed positive test results with Factor XIIIa (90.9%), vimentin (100%), and CD68 (100%) and negative test results with CD1a, smooth muscle actin, and S-100 protein stains. Tumor excision was the treatment for choice. CONCLUSION: Adult xanthogranuloma most commonly manifested as the nodular form of the disease on the head and neck of men in their late 20s. Histopathologically, the classic Touton cell-rich stage was most commonly observed, followed by the stage of early predominantly mononuclear infiltration. This was a single-center, small-sized retrospective study; however, we expect the results of this study to contribute to a better understanding of adult xanthogranuloma.
Actins ; Adult ; Child ; Coloring Agents ; Eosinophils ; Factor XIIIa ; Female ; Giant Cells ; Head ; Histiocytes ; Humans ; Incidence ; Infant ; Male ; Muscle, Smooth ; Neck ; Retrospective Studies ; S100 Proteins ; Vimentin ; Xanthogranuloma, Juvenile

Rosai-Dorfman disease, also known as the sinus histiocytosis with massive lymphadenopathy, is a rare and benign histioproliferative disease in which lymphadenopathy results from infiltration and dilatation of lymph node sinuses by large histiocytes. We experienced a case of a 59-year-old man, presenting bilateral cervical masses with pain since one month ago. Radiologically, there were multiple enlarged lymph nodes with homogenous contrast enhancement at both cervical areas. Excisional biopsy revealed that the tumor was consistent with the Rosai-Dorfman disease. The patient was treated successfully with corticosteroid. Herein, we report our experiences with literature reviews.
Biopsy ; Dilatation ; Histiocytes ; Histiocytosis ; Histiocytosis, Sinus ; Humans ; Lymph Nodes ; Lymphatic Diseases ; Middle Aged ; Neck

Histiocytic sarcoma is a rare hematologic malignancy, with very few cases of primary histiocytic sarcoma of the breast described in English scientific literature. Herein, we describe a case of primary histiocytic sarcoma of the breast in a 75-year-old woman, with no clinical history of malignant tumors, who presented with a palpable solitary breast mass. Microscopically, the resected breast mass showed large pleomorphic cells, some multinucleated giant cells, and admixed inflammatory components. The pleomorphic tumor cells further showed a diffuse, noncohesive growth pattern, an abundant eosinophilic cytoplasm, and strong and diffuse immunoreactivity for cluster of differentiation (CD) 68 and CD163. Furthermore, a whole-body positron-emission tomography/computed tomography using deoxy-2-[¹⁸F]fluoro-D-glucose performed after surgery showed no other masses or lesions. After surgical excision, the patient was followed up, and no evidence of tumor recurrence or metastasis was noted.
Aged ; Breast ; Cytoplasm ; Eosinophils ; Female ; Giant Cells ; Hematologic Neoplasms ; Histiocytes ; Histiocytic Sarcoma ; Humans ; Neoplasm Metastasis ; Recurrence

A 33-year-old male had a 22-year history of generalized xanthogranulomas but had a normal lipid profile. He also developed ulcerating plaques on his arm and back that were consistent with cutaneous tuberculosis on histopathologic and polymerase chain reaction PCR studies. In a normolipemic patient with generalized xanthogranulomas, a reactive granulomatous response of histiocytes to infection is explored since these share a common CD 14+ precursor with the macrophages that are vital in tuberculosis.

Erdheim-Chester disease (ECD) is a form of non–Langerhans cell histiocytosis that most commonly involves the skeletal system. We report an unusual case of ECD presenting as an anterior mediastinal tumor without skeletal involvement. A 60-year-old man with no remarkable medical history was referred for evaluation of a mediastinal mass. The patient underwent surgical excision of the tumor via video-assisted thoracoscopic surgery. Histologic examination revealed marked proliferation of atypical histiocytes with sclerosis, and the results of immunohistochemical staining were suggestive of ECD.
Erdheim-Chester Disease* ; Histiocytes ; Histiocytosis ; Humans ; Mediastinum ; Middle Aged ; Sclerosis ; Thoracic Surgery, Video-Assisted

BACKGROUND: Warthin-like variant of papillary thyroid carcinoma (WLV-PTC) is a relatively rare variant of papillary thyroid carcinoma with favorable prognosis. However, preoperative diagnosis using fine-needle aspiration (FNA) specimens is challenging especially with lymphocytic thyroiditis characterized by Hürthle cells and lymphocytic background. To determine a helpful cytological differential point, we compared WLV-PTC FNA findings with conventional papillary thyroid carcinoma with lymphocytic thyroiditis (PTC-LT) and conventional papillary thyroid carcinoma without lymphocytic thyroiditis (PTC) regarding infiltrating inflammatory cells and their distribution. Preoperative diagnosis or potential for WLV-PTC will be helpful for surgeons to decide the scope of operation. METHODS: Of the 8,179 patients treated for papillary thyroid carcinoma between January 2007 and December 2012, 16 patients (0.2%) were pathologically confirmed as WLV-PTC and four cases were available for cytologic review. For comparison, we randomly selected six PTC-LT cases and five PTC cases during the same period. The number of intratumoral and background lymphocytes, histiocytes, neutrophils, and the presence of giant cells were evaluated and compared using conventional smear and ThinPrep preparations. RESULTS: WLV-PTC showed extensive lymphocytic smear with incorporation of thyroid follicular tumor cell clusters and frequent histiocytes. WLV-PTC was associated with higher intratumoral and background lymphocytes and histiocytes compared with PTC-LT or PTC. The difference was more distinct in liquid-based cytology. CONCLUSIONS: The lymphocytic smear pattern and the number of inflammatory cells of WLV-PTC are different from those of PTC-LT or PTC and will be helpful for the differential diagnosis of WLV-PTC in preoperative FNA.
Biopsy, Fine-Needle ; Diagnosis ; Diagnosis, Differential ; Giant Cells ; Hashimoto Disease ; Histiocytes ; Humans ; Lymphocytes ; Neutrophils ; Prognosis ; Surgeons ; Thyroid Gland ; Thyroid Neoplasms ; Thyroiditis, Autoimmune