Imaging features of primary extranodal histiocytic sarcoma: report of two cases and a review of the literature

Histiocytic sarcoma mimicking localized tenosynovial giant cell tumor in the pediatric foot: A rare case report with MRI Findings

We present a rare case of histiocytic sarcoma (HS) occurring in the foot of a 12-year-old male, initially misdiagnosed as localized tenosynovial giant cell tumor (TSGCT). HS is an exceptionally uncommon hematologic malignant neoplasm, with its occurrence in children and extranodal sites being even rarer. To our knowledge, this is the first reported case of extranodal HS in the foot, emphasizing comprehensive MRI findings. Initially, the patient was diagnosed with TSGCT based on histological results following surgical resection. However, after recurrence and subsequent surgical resection, histological and immunochemical analyses led to a revised diagnosis of HS. This report focuses on the MRI findings of HS, highlighting the distinctions from localized TSGCT. While both conditions share histopathological similarities, immunohistochemical tests are crucial for accurate diagnosis. The report underscores the importance of differentiating HS for appropriate treatment.

Rare Multisystem Histiocytic Sarcoma on 18F-FDG PET/CT

Histiocytic sarcoma (HS) is a rare malignancy with morphologic and immunophenotypic features indicating histiocytic differentiation. We present a case of HS with multisystem involvement, including an obstructing mass in the pancreatic head. ¹⁸F-FDG PET/CT is a valuable tool in staging this rare entity and in assessing the response to therapy. Knowing the diverse metastatic pattern of HS will help avoid imaging pitfalls on clinical ¹⁸F-FDG PET/CT scans.

Small bowel and lung histiocytic sarcoma revealed by acute peritonitis: A case report with review of literature

INTRODUCTION AND IMPORTANCE

Histiocytic sarcoma (HS) is a rare malignant neoplasm showing morphologic and immunohistochemical features of histiocytes. It is characterized typically by extranodal presentation and a poor clinical course, particularly in cases with disseminated disease.

CASE PRESENTATION

This report documents a case of bifocal and aggressive HS in small bowel and lung revealed by acute peritonitis in a 63-year-old man.

CLINICAL DISCUSSION

Despite its rarity, we believe that the correct diagnosis of HS is crucial for clinical treatment and prognostic prediction.

CONCLUSION

The collection of additional cases of HS are important to obtain further progress in prognosis and guide treatment decisions.

New onset headache caused by histiocytic sarcoma of the spinal cord and leptomeninges: a case report

Background

Headache due to raised intracranial pressure is rarely caused by spinal lesions. We describe a patient with primary histiocytic sarcoma who presented with a new onset headache with features of raised intracranial pressure and subtle signs of cauda equina syndrome due to predominant lower spinal cord infiltration and minimal intracranial involvement.

Case

A previously well 54-year-old man presented with a 2-month history of new onset headache with features of raised intracranial pressure. Progression of lower limb weakness was delayed and mild with diagnostic delay resulting from the primary presentation with headache leading to an initial focus on cerebral pathology. Subsequent investigations revealed a previously unreported presentation of primary histiocytic sarcoma infiltrating the cauda equina causing raised intracranial pressure headache.

Conclusion

This case highlights the importance of a broad search in the investigation of new onset raised intracranial pressure headache, including imaging of the lower spinal cord. Primary histiocytic sarcoma should be considered in the differential diagnosis of this rare syndrome.

Balancing risk in a patient with primary bone histiocytic sarcoma during pregnancy: Case report and review of the literature

INTRODUCTION AND IMPORTANCE

Histiocytic sarcoma (HS) is a rare, aggressive malignant neoplasm of hematopoietic cell origin. Primary HS of the proximal humerus, without involvement of lymph nodes or bone marrow, or systemic features, is very rare.

CASE PRESENTATION

We report a rare case of primary bony HS of the proximal humerus without bone marrow involvement in a healthy 33-year-old pregnant woman. She was successfully treated with surgical resection during pregnancy and radiotherapy post-delivery.

CLINICAL DISCUSSION

This is the first report of a patient with primary bony HS during pregnancy. This highlights the fact that although HS is a neoplasm of hemolymphoid cell lineage, it frequently arises in non-lymphoid organs.

CONCLUSION

This case emphasizes the importance of a multidisciplinary approach and the need for balancing treatment risk in a patient with primary bone HS during pregnancy.

Histiocytic Sarcoma Arising From a Long Bone: Report of Two Cases

Histiocytic sarcoma is a rare, but aggressive malignant neoplasm of monocyte/macrophage lineage with a wide age distribution. Bone involvement is exceedingly rarer compared to the lymph node, skin, and soft tissue, and no long bone involvement has been reported in the English literature. We here report 2 cases of histiocytic sarcoma involving the long bone: one from the femur of a 77-year-old female, status post the placement of an intramedullary nail for subtrochanteric hip fracture; the other from the radius of a 3-year-old female with no significant medical history. Radiologic imaging showed highly destructive lesions in both cases with soft-tissue extension. Microscopy in both cases showed sheets of polygonal mononuclear cells with abundant eosinophilic cytoplasm, prominent nucleoli, and frequent mitosis. Hemophagocytosis were also identified. Immunohistochemistry showed that the lesional cells were strongly diffusely positive for CD68 and CD163. The first patient deteriorated rapidly, despite the aggressive treatment of amputation and chemotherapy. However, the second patient is disease free 36 months post the treatment of amputation only. We conclude that the long bone could be the primary site of histiocytic sarcoma. Its prognosis could be very variable and it is difficult to predict its behavior based on morphological evaluation only.

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.

Imprint cytology of histiocytic sarcoma manifesting as a retroperitoneal mass: A valuable aid for frozen section diagnosis

Histiocytic sarcoma (HS) is a comparatively rare hematolymphoid neoplasm. Differential diagnosis of this entity has generally been proven to be so difficult that extensive immunohistochemical staining is required to confirm its presence. We herein present a case of HS manifesting as a retroperitoneal mass in which imprint cytology (IC) contributed to the diagnosis. A 77-year-old man was referred for the evaluation of a colonic tubulovillous polypoid lesion. Preoperative imaging revealed a 3 cm-sized polypoid lesion in the transverse colon. Incidentally, a retroperitoneal mass of 8 cm in the left para-aortic region was also detected. Diff-Quik stained IC slides were prepared as an adjunct to intraoperative pathology consultation. The smear exhibited moderate cellularity involving loosely cohesive cell clusters with intervening delicate vasculature. Most of the tumor cells consisted of large single cells with abundant eosinophilic cytoplasm that was vacuolated and foamy. The nuclei were predominantly large and eccentrically located. Mitotic figures were minimal in number and finely granular brown pigments were occasionally observed. A frozen section diagnosis was reported as a malignant neoplasm, and a histologic diagnosis of HS was confirmed by conducting a battery of immunohistochemical stains: negative for pan-cytokeratin, EMA, CD117, HMB45, Melan A, CD30, PAX5, CD20, S-100, and CD23 but strong positive for vimentin and CD68. This entity is rarely described in terms of cytopathologic features. This case study highlights how cytopathologists should be aware of HS as a retroperitoneal lesion and should become familiar with cytomorphologic features.

Histiocytic sarcoma: New insights into FNA cytomorphology and molecular characteristics

BACKGROUND

Histiocytic sarcoma (HS) is a rare malignant neoplasm showing morphologic and immunophenotypic features of histiocytes. Molecular characteristics of HS and fine-needle aspiration (FNA) criteria for its diagnosis have not been established.

METHODS

A case series of HS in 8 FNA samples from 6 patients was reviewed along with histopathologic and clinical data. Immunohistochemistry was performed on cell blocks (3 cases), core biopsies (5 cases), and surgical specimens (4 cases). Targeted-exome next-generation sequencing (NGS) was performed on surgical resection specimens in 4 cases.

RESULTS

Four patients had a known history of hematolymphoid malignancy. Cytomorphologic features included variably cellular smears composed of large epithelioid cells with reniform nuclei and abundant vacuolated cytoplasm, in an inflammatory background, with occasional cytophagocytosis and lymphoglandular bodies. Marked pleomorphism, multinucleated monster cells, and binucleated histiocytoid cells with partially overlapping, eccentrically placed nuclei resembling Pac-Man were common. Most cases expressed histiocytic markers CD68 (6 of 7 cases), CD163 (5 of 5 cases), and PU.1 (3 of 4 cases). In 3 cases, NGS analysis revealed alterations in lysine methyltransferase 2D (KMT2D)/mixed-lineage leukemia 2 (MLL2), a gene involved in chromatin regulation and previously implicated in the pathogenesis of follicular lymphoma.

CONCLUSIONS

Although diagnosing HS with FNA alone is extremely challenging, the presence of pleomorphic and epithelioid large cells with binucleation and/or multinucleation in an inflammatory background should prompt the diagnosis of HS with judicious use of confirmatory histiocytic lineage markers. The detection of recurrent KMT2D/MLL2 alterations implicates epigenetic regulation in the pathogenesis of HS and supports the notion of transdifferentiation from a genetically similar but phenotypically distinct tumor of a different lineage. Cancer Cytopathol 2017;125:604-14. © 2017 American Cancer Society.

Enhanced CT and FDG PET/CT in Histiocytic Sarcoma of the Pericardium

Histiocytic sarcoma is an extremely rare and aggressive malignant neoplasm of presumed hematopoietic origin. Lymph nodes are the most common sites of involvement. A variety of extranodal sites can be involved, particularly the gastrointestinal tract, soft tissue, skin, and spleen. Radiologic findings of histiocytic sarcoma have been rarely reported. We present a case with histiocytic sarcoma in pericardium, which is an unusual site. Enhanced chest CT showed remarkable enhancement of the tumor. On FDG PET/CT, the tumor showed intense FDG uptake.

A rare case of paediatric histiocytic sarcoma of the maxilla and mandible

Histiocytic sarcoma is an extremely rare malignant neoplastic proliferation of the haematopoietic cells. Very few cases have been reported in the paediatric age group. Imaging features have been rarely described in the literature. It can involve any region of the body; however, it most commonly involves the lymph nodes. Its imaging appearance can mimic lymphoproliferative disorders; however, with the advent of new immunohistochemical markers, the diagnosis of HS has become more reliable. We report an unusual case of primary bone involvement by HS with multiple lesions in the facial bones of a 2-year-old female who presented with tooth and mandibular tenderness.

Viral oncolysis - can insights from measles be transferred to canine distemper virus?

Neoplastic diseases represent one of the most common causes of death among humans and animals. Currently available and applied therapeutic options often remain insufficient and unsatisfactory, therefore new and innovative strategies and approaches are highly needed. Periodically, oncolytic viruses have been in the center of interest since the first anecdotal description of their potential usefulness as an anti-tumor treatment concept. Though first reports referred to an incidental measles virus infection causing tumor regression in a patient suffering from lymphoma several decades ago, no final treatment concept has been developed since then. However, numerous viruses, such as herpes-, adeno- and paramyxoviruses, have been investigated, characterized, and modified with the aim to generate a new anti-cancer treatment option. Among the different viruses, measles virus still represents a highly interesting candidate for such an approach. Numerous different tumors of humans including malignant lymphoma, lung and colorectal adenocarcinoma, mesothelioma, and ovarian cancer, have been studied in vitro and in vivo as potential targets. Moreover, several concepts using different virus preparations are now in clinical trials in humans and may proceed to a new treatment option. Surprisingly, only few studies have investigated viral oncolysis in veterinary medicine. The close relationship between measles virus (MV) and canine distemper virus (CDV), both are morbilliviruses, and the fact that numerous tumors in dogs exhibit similarities to their human counterpart, indicates that both the virus and species dog represent a highly interesting translational model for future research in viral oncolysis. Several recent studies support such an assumption. It is therefore the aim of the present communication to outline the mechanisms of morbillivirus-mediated oncolysis and to stimulate further research in this potentially expanding field of viral oncolysis in a highly suitable translational animal model for the benefit of humans and dogs.