Histiocytic sarcoma

Favorable outcome of a histiocytic sarcoma patient treated with immune checkpoint inhibitor: a case report

Introduction and Importance

Histiocytic sarcoma (HS) is an extremely rare malignancy in which there has been no standard treatment approach. Some preclinical studies have provided rationales for the application of immunotherapy in advanced HS.

Case Presentation

The authors reported a case of a 61-year-old patient with metastatic HS who had a rapid progression on ifosfamide, carboplatin, and etoposide chemotherapy. The authors performed PD-L1 testing, which showed a strong positivity in 90% of tumor cells. The patient was then treated with pembrolizumab 200 mg every 3 weeks. He refused palliative radiotherapy. A dramatic response in all sites was recorded on the PET-CT scan after three cycles. He was maintained on pembrolizumab, reaching over 30 months without disease progression.

Clinical Discussion

Recent molecular data suggests there could be a role of immunotherapy in HS. In our patient, the disease was refractory to chemotherapy and pembrolizumab has been given based on the strong PD-L1 expression. Response to immunotherapy has also been recorded in several cases with malignant histiocytic neoplasm.

Conclusion

Immunotherapy might bring sustained disease remission in PD-L1 high expression HS and further studies evaluating the role of immune checkpoint inhibitor in this disease are warranted.

Neoplastic or inflammatory? A case report of Sweet syndrome with CD30+ cells in a patient with B-lymphoblastic leukemia

CD30+ cells are typically part of lymphoproliferative disorders but can also be seen in inflammatory dermatoses. We present a case of 47-year-old man with a history of B-lymphoblastic leukemia (B-ALL) who presented with fever, leukocytosis, and papulonodular skin lesions, involving the extremities and trunk. A punch biopsy specimen demonstrated papillary dermal edema with a neutrophilic and histiocytic infiltrate extending into the subcutis. The infiltrate also harbored scattered large cells that were positive for CD30 and demonstrated the immunohistochemical profile of monocytes. A diagnosis of histiocytoid Sweet syndrome with CD30+ cells was made. The case is unique, demonstrating a combination of Sweet syndrome variants with subcutis involvement, histiocytoid morphology, and large CD30+ cells. A prior history of B-ALL and immunohistochemical profile of monocytes with immature morphology broadened the differential diagnosis and added to the diagnostic challenge.

Cancer-Immunity Cycle and Therapeutic Interventions- Opportunities for Including Pet Dogs With Cancer

The tumor-immune interplay represents a dynamic series of events executed by cellular and soluble participants that either promote or inhibit successful tumor formation and growth. Throughout a tumor’s development and progression, the host organism’s immune system reacts by generating anti-cancer defenses through various incremental and combinatorial mechanisms, and this reactive orchestration is termed the cancer-immunity cycle. Success or failure of the cancer-immunity cycle dictates the fate of both host and tumor as winner or loser. Insights into how the tumor and host immune system continuously adapt to each other throughout the lifecycle of the tumor is necessary to rationally develop new effective immunotherapies. Additionally, the evolving nature of the cancer-immunity cycle necessitates therapeutic agility, requiring real-time serial assessment of immunobiologic markers that permits tailoring of therapies to the everchanging tumor immune microenvironment. In order to accelerate advances in the field of immuno-oncology, this review summarizes the steps comprising the cancer-immunity cycle, and underscores key breakpoints in the cycle that either favor cancer regression or progression, as well as shaping of the tumor microenvironment and associated immune phenotypes. Furthermore, specific large animal models of spontaneous cancers that are deemed immunogenic will be reviewed and proposed as unique resources for validating investigational immunotherapeutic protocols that are informed by the cancer-immunity cycle. Collectively, this review will provide a progressive look into the dynamic interplay between tumor and host immune responses and raise awareness for how large animal models can be included for developing combinatorial and sequenced immunotherapies to maximizing favorable treatment outcomes.

Spontaneous Disseminated Histiocytic Sarcoma in a Bengal Tiger (Panthera tigris tigris)

A 16-year-old, female, captive Bengal tiger (Panthera tigris tigris) had a history of a recurrent subcutaneous mass. After two attempts at surgical removal, euthanasia was elected during the third surgical attempt due to the degree of neoplastic infiltration. At necropsy, a large subcutaneous mass infiltrated the dermis, subcutis and abdominal wall with metastasis to the lungs, spleen and adrenal glands. Microscopically, the neoplasm formed nodules comprising sheets of round cells with large irregular nuclei. Toluidine blue and Giemsa stains were negative. An immunohistochemistry panel revealed membranous and cytoplasmic labelling with ionized calcium-binding adaptor molecule 1 (IBA1), cytoplasmic labelling with vimentin but no labelling with multiple myeloma oncogene 1 (MUM1), CD20 or pancytokeratin markers. Based on the gross distribution and histological and immunohistochemistry features, a diagnosis of disseminated histiocytic sarcoma was made. To the best of our knowledge, this is the first record of disseminated histiocytic sarcoma in a captive Bengal tiger.

Histiocytic sarcoma arising from a lymph node: a diagnostic conundrum

Histiocytic Sarcoma (HS) is extremely rare, with only a few hundred cases reported in the literature. The majority of patients present with symptoms due to unifocal or multifocal extra-nodal disease. Less than 20% of these cases show solitary involvement of a lymph node. We report a case of a solitary HS in a 53-year-old woman presenting with a 2.7-cm right groin mass arising from an inguinal lymph node. The initial cytologic examination of the tissue showed a high-grade spindle-shaped morphology with high-grade mitotic activity. A high-grade sarcoma was initially considered considering the absence of normal lymphoid aggregate and the presence of high-grade cytologic features in the cells. To evaluate the tumor in its entirety, the mass was surgically excised. A histological examination of the tumor showed focal rimming of the lymphoid tissue at the periphery and a centrally located stellate necrotic focus. The tumor cells had an epithelioid to spindle cell morphology along with large uniform nuclei and prominent nucleoli. A high mitotic index was present. Immunohistochemistry (IHC) stains showed strong positivity for CD68, CD163, and Vimentin, and were weakly positive for SMA and CD45. Based on the histologic and clinical examination, a diagnosis of HS was made. Multiple malignancies can mimic HS histopathology and the rarity of this tumor makes the diagnosis more challenging. No fine-needle aspiration (FNA) criteria for its diagnosis have been recognized. Herein, we report a rare case of an isolated HS involving a lymph node which resembled high-grade sarcoma on the FNA biopsy to raise awareness among our surgical pathologist colleagues.

Nonepithelial Tumors of the Larynx: Single-Institution 13-Year Review with Radiologic-Pathologic Correlation

Nonepithelial tumors of the larynx are rare and represent a minority of all laryngeal neoplasms. Imaging has an important role in the diagnosis, treatment planning, and surveillance of these entities. However, unfamiliarity with these neoplasms can cause diagnostic difficulties for radiologists, especially because many of the imaging findings are nonspecific. By using a systematic approach based on clinical history, patient age and gender, lesion location, endoscopic results, and specific imaging findings, the differential diagnosis can often be narrowed. These tumors typically affect the submucosal layer, so if a tumor has an intact mucosa at endoscopy, a nonepithelial neoplasm is the most likely diagnosis. Nonepithelial tumors of the larynx can arise from the laryngeal cartilage or muscle or from the surrounding lymphoid tissue or blood vessels. Consequently, imaging findings typically correspond to the specific cell type from which it originated. Recognizing specific features (eg, metaplastic bone formation, macroscopic fat, or enhancement pattern) can often help narrow the differential diagnosis. In addition, identification of noncircumscribed borders of the lesion and invasion of the adjacent structures is key to diagnosis of a malignant process rather than a benign neoplasm. Understanding the pathologic correlation is fundamental to understanding the radiologic manifestations and is ultimately crucial for differentiation of nonepithelial laryngeal neoplasms. Online supplemental material is available for this article. ^©RSNA, 2020.

Pediatric multifocal histiocytic sarcoma- a fatal diagnosis not to miss!

Histiocytic sarcoma (HS) is a rare hematolymphoid malignant neoplasm with an aggressive clinical course. It can arise de novo or from low-grade B-cell lymphoma. We describe the case of a 16-year-old boy referred to our hospital with generalized lymphadenopathy, weight loss, and decreased appetite for one month. The patient died undiagnosed on the 7^th day of hospitalization. Lymph node and bone marrow biopsies were performed one day before the patient died. The lymph node biopsy revealed an architectural effacement with a diffuse proliferation of large pleomorphic neoplastic cells containing large, multilobulated nuclei, coarse vesicular chromatin, prominent nucleoli, and a moderate amount of eosinophilic cytoplasm. The bone marrow aspiration smears and biopsy also showed evidence of infiltration by these above-mentioned cells. Based on the morphology, along with the exclusion of many differential diagnoses by an extensive panel of immunohistochemical markers, a diagnosis of HS was made. This case report aims at evaluating all the clinical and immunophenotypic features of a case of HS with multifocal presentation and an aggressive clinical course in order to give a correct and definite diagnosis at the proper time.

Rare Presentation of a Rare Tumor: Histiocytic Sarcoma

An 84-year-old male, with a large gouty tophus over the left elbow for 20 years, developed a new left elbow area mass about three months ago and presented to the emergency department (ED) with complaints of bleeding from that left elbow area mass after a small blunt injury. Initially diagnosed as olecranon bursitis, it had the worsening size and atypical growth associated with persistent leukocytosis. After being evaluated by multiple specialties, including infectious diseases, orthopedic surgery, and rheumatology, it was decided to do a biopsy, which resulted in the diagnosis of histiocytic sarcoma.

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.