Primary leptomeningeal histiocytic sarcoma in a patient with a good outcome: a case report and review of the literature

A rare case of primary central nervous system histiocytic sarcoma harboring a novel ARHGAP45::BRAF fusion: a case report and literature review

INTRODUCTION

Patients with histiocytic sarcoma occurring in the central nervous system (CNS) are rare and have a very poor prognosis. The increased use of molecular diagnostic approaches in solid tumors has brought more opportunities for the diagnosis and treatment of central nervous system histiocytic sarcoma (CNSHS).

CASE DESCRIPTION

A 9-year-old girl was admitted to the hospital with pain in her head and neck, as well as vomiting. Imaging scans showed a prominent abnormality in the anterior falciform region, and histopathology revealed the presence of CD68 (+) and CD163 (+) cells, leading to a preliminary diagnosis of primary intracerebral CNSHS. Molecular profiling tests identified a new variant of ARHGAP45::BRAF fusion in this case, which has not been reported in any other tumor. The patient underwent surgical removal of the tumor and will require long-term monitoring.

CONCLUSION

The presence of the BRAF point mutation, predominantly BRAF p.V600E, has been documented in prior literature of CNSHS. This is the first case of pediatric histiocytic sarcoma in the anterior falciform region who has a unique ARHGAP45::BRAF fusion. The findings of our study indicate that a broader range of molecular assays should be employed in the diagnosis of CNSHS and opens up new possibilities for the treatment of the patient.

Primary intracranial histiocytic sarcomas: a report of six cases and a pooled analysis of individual patient data

OBJECTIVE

Primary intracranial histiocytic sarcomas (PIHSs) are extremely rare with limited reported cases, making their prognostic factors and management uncertain. This study aims to describe the clinical characteristics of PIHSs and propose a treatment protocol for this entity.

METHODS

Clinical data were collected from six patients diagnosed with PIHSs at Beijing Tiantan Hospital between March 2011 and October 2022. Additionally, a comprehensive search of the PubMed database was conducted using the keywords "primary intracranial" or "primary central nervous system" combined with "histiocytic sarcoma" or "histiocytic sarcomas" between 1996 and 2022, identifying 24 cases. A pooled analysis of individual patient data was performed to assess risk factors for overall survival (OS).

RESULTS

The six cases included four males and two females, with a mean age of 42.2 ± 13.3 years. In total, 24 cases of PIHSs were identified from previous studies. Multivariate Cox regression analysis revealed that gross total resection (GTR) was the only factor predicting a longer OS (p = 0.027). Kaplan-Meier analysis demonstrated that GTR (p = 0.0013), solitary lesions (p = 0.0048), and radiotherapy (p = 0.0492) were associated with a longer OS.

CONCLUSION

PIHSs are rare brain tumors with poor clinical prognosis. Patients with solitary lesions have a longer OS than those with multifocal lesions. Gross total resection must be the first choice. Radiotherapy may bring benefits for these patients, but chemotherapy may not be useful. Further studies involving larger cohorts are necessary to validate these findings.

Primary histiocytic sarcoma of the central nervous system: a case report with platelet derived growth factor receptor mutation and PD-L1/PD-L2 expression and literature review

Background

Histiocytic sarcoma (HS) is an aggressive malignant neoplasm. HS in the central nervous system is exceptionally rare and associated with a poor prognosis. This report documents a case of primary HS of the central nervous system with treatment including surgery, radiotherapy, and chemotherapy.

Case presentation

Our patient was a 47 year old female presenting with progressive ataxia, headaches, imbalance, nausea, vomiting, and diplopia. MRI showed a heterogeneously enhancing lesion approximately 2.9 × 3.0 × 2.3 cm centered upon the cerebellar vermis with mild surrounding vasogenic edema and abnormal enhancement of multiple cranial nerves. The patient underwent surgical debulking, which revealed histiocytic sarcoma with grossly purulent drainage. Staging revealed diffuse leptomeningeal involvement, primarily involving the brain and lower thoracic and lumbar spine. She underwent adjuvant radiotherapy to the brain and lower spine and was started on high dose methotrexate. However, she experienced progressive disease in the cervical and thoracic spine as well as pulmonary involvement. Genomic sequencing of her tumor showed a mutation in the platelet-derived growth factor receptor A (p.V0681) which could be targeted with Dasatinib. However, she did not tolerate Dasatinib and she succumbed to progressive disseminated disease eight months from original diagnosis. Our pathologic evaluation also revealed expression of PD-L1 and PD-L2 by tumor cells raising the potential therapeutic role for immune checkpoint inhibition.

Conclusions

This case provides an example of effective CNS control with resection and moderate doses of radiation therapy. A review of the literature confirms aggressive multidisciplinary treatment is the most effective treatment against this disease. In addition, genomic sequencing may play an important role in determining new therapeutic options. However, CNS histiocytic sarcoma remains an aggressive disease with a propensity for early widespread dissemination and few long term survivors.

Case of primary central nervous system histiocytic sarcoma with prominent proliferation of histiocytic cells between the trabeculae of reactive glial cells

Histiocytic sarcoma (HS) is an extremely rare malignant neoplasm that exhibits morphologic and immune-phenotype evidence of histiocytic differentiation. The disease most commonly involves the lymph nodes, gastrointestinal tract, skin, and soft tissue, as well as in the central nervous system (CNS) being relatively rare. Here we report a case of primary CNS HS with unusual histopathological characteristics. A 65-year-old woman presented with CNS HS in the left frontal lobe region, showing two distinct histological patterns. Approximately half of the lesion displayed histological characteristics typical of HS, including diffuse invasion of large round-to-ovoid pleomorphic cells, with mitotic figures (Ki-67 index: 30%) and coagulative necrotic foci. The other half exhibited prominent proliferation of histiocytic cells between the trabeculae of reactive glial cells, with rare mitotic figures (Ki-67 index: < 1%) and no necrotic foci. There were transitions between two morphologies. The HS tumor cells and the histiocytic cells between the trabeculae of reactive glial cells possessed nearly identical histomorphologic and immunophenotypic features, although the HS tumor cells showed a more pronounced degree of cytologic atypia and mitotic activity. To our knowledge, this is the first reported case of HS with prominent proliferation of the histiocytic cells between the trabeculae of reactive glial cells. Here we present the detailed histological, immunohistochemical, and molecular findings. Investigating cases of HS may provide insight into the pathogenesis of this disease.

Primary central nervous system histiocytic sarcoma: A case report and review of literature

RATIONALE

Primary central nervous system histiocytic sarcoma (PCNSHS) is a rare lymphohematopoietic tumor with a histiocytic cell origin. To our knowledge, only 28 cases have been published in English and 2 cases in Chinese.

PATIENT CONCERNS

A 49-year-old Asian female presented to the hospital with a 2 month history of hypomnesia, odynophagia, and gait disorder. Physical examination demonstrated decreased lower extremity muscle strength. The patient denied a history of malignancy.

DIAGNOSES

Radiology demonstrated a lesion in parietal lobe with uniformenhancement. Histologic analysis showed pleomorphic tumor cells with a loose arrangement, effacing the normal brain tissue. The tumor cells exhibited abundant eosinophilic cytoplasm, highly atypical nuclei and predominant nucleoli. Immunohistochemistry revealed positive immunoreactivity for CD45, lysozyme, CD68, and CD163, and negative for pan-cytokeratin (CK), epithelial membrane antigen (EMA), glial fibrillary acidic protein (GFAP), CD3, CD20, CD1a, CD79a, CD138, oligodendrocyte transcription factor (olig2), CD15, melan-A, CD30, CD21, CD35, Human Melanoma Black-45 (HMB45), and anaplastic lymphoma kinase-1 (ALK-1). The diagnosis of PCNSHS was rendered.

INTERVENTIONS

The patient underwent complete surgical resection and adjuvant radiotherapy.

OUTCOMES

Follow-up information shows the patient died 8 months following the initial diagnosis.

LESSONS

PCNSHS is extremely rare with an aggressive clinical course. Immunohistiochemistry is necessary to make this diagnosis and to exclude other primary intracranial and lymphohematopoietic tumors. Further research is required to improve the outcome of patients with PCNSHS.

Infection or Glioma? The False Dilemma of Primary Central Nervous System Histiocytic Sarcoma

BACKGROUND

Primary central nervous system (CNS) histiocytic sarcoma is an extremely rare lymphoproliferative disorder that affects the CNS and behaves aggressively. Only 27 cases of primary CNS histiocytic sarcoma have been reported. The paucity of literature on this entity has made diagnosis and treatment difficult both for the surgeon and the pathologist.

CASE DESCRIPTION

In this case of primary CNS histiocytic sarcoma, a middle-aged woman presented from an outside institution with a supposed cerebellar abscess. Intraoperative frozen pathology was initially interpreted as high-grade glioma; however, final pathology demonstrated histiocytic sarcoma.

CONCLUSIONS

This report makes a significant contribution to the literature on this rare malignant disease by outlining a similar presentation among several cases and providing a thorough overview of existing criteria for diagnosis and management.

Primary histiocytic sarcoma presenting as diffuse leptomeningeal disease: Case description and review of the literature

Histiocytic sarcoma is a rare malignant neoplasm arising most commonly in lymph nodes, intestinal tract, skin and soft tissue. The incidence of primary CNS histiocytic sarcoma is even rarer with a total of just 27 cases reported in the literature so far. Herein we describe the first autopsy case of histiocytic sarcoma presenting as a diffuse leptomeningeal disease in absence of a CNS tumor-forming parenchymal lesion. The clinical, pathological and immunophenotypic features are described and an updated literature review on primary CNS histiocytic sarcoma is included.

Primary cerebral histiocytic sarcoma in childhood: a case report of protracted survival and review of the literature

INTRODUCTION

Histiocytic sarcoma (HS) of the central nervous system (CNS) is exceptionally rare in pediatric patients, historically associated with an exceptionally poor prognosis. Here, the authors present a novel case of protracted progression-free survival following surgical excision, radiotherapy and temozolomide.

CASE REPORT

A 15-year-old Caucasian girl presented with a two-month history of headache, diplopia, vomiting, lethargy, weight loss and neurocognitive deterioration without gross neurological deficit on physical examination. Magnetic resonance imaging (MRI) of the brain identified a 5.8 × 4.7 × 4.0 cm lesion in the right frontal lobe with associated mass effect and no dissemination. Following two surgical procedures, gross total resection was achieved. Histology and immunohistochemistry confirmed HS, with strong CD163 staining. After focal radiotherapy with concomitant temozolomide, and a further seven cycles of temozolomide, the patient made an excellent recovery and is recurrence free without neurological deficit, 23 months following presentation.

CONCLUSION

To the authors' knowledge, this is the first incidence of a prolonged, functionally preserved and recurrence-free outcome following a diagnosis of HS within the CNS of a pediatric patient. We suggest early diagnosis prior to dissemination and complete surgical resection as an essential treatment goal in this rare disease.

Isolated III cranial nerve palsies may point to primary histiocytic sarcoma

Primary histiocytic sarcoma (HS) of the central nervous system (CNS) is a rare haematopoietic neoplasm. The inconsistent terminology and diagnostic criteria currently used for CNS HS have complicated the appreciation of the clinical aspects of the disease. The main differential diagnoses are non-Hodgkin's lymphoma, reactive histiocytic proliferation, dendritic cell neoplasm, undifferentiated carcinoma, inflammatory pseudotumour, Rosai-Dorfman disease and abscess. The true diagnosis of CNS HS requires an extensive immunophenotypic workup using specific histiocytic markers, such as CD163, with the exclusion of markers of other cell lineages. This clinicopathological case report describes an improved approach towards the differential diagnosis of CNS HS.