Immunocompetent murine models recapitulate the heterogeneous tumor immune microenvironment of human liposarcoma.

Purpose: Liposarcoma (LPS) is the most common soft tissue sarcoma. Well-differentiated LPS (WDLPS) can progress to dedifferentiated LPS (DDLPS), a more aggressive form with higher metastatic potential and poor response to existing therapies. Progress in understanding and treating LPS has been limited.

An immunocompetent mouse model of liposarcoma.

Liposarcoma (LPS) is the most prevalent soft tissue sarcoma. The most common biological subtypes are well-differentiated (WDLPS), a low-grade disease that can evolve to high-grade dedifferentiated LPS (DDLPS), with increased rates of recurrence and metastasis and low response rates to chemotherapy and targeted therapies. Preclinical testing of immunotherapeutics for LPS has been held back by the lack of an immunocompetent mouse model.

Hemophagocytosis on ascitic fluid cytology: Diagnosis of HLH.

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening syndrome of pathologic immune response characterized by excessive activation of macrophages. Hemophagocytosis is one of the diagnostic criteria for HLH, and it usually involves the bone marrow, spleen, lymph nodes, or any part of the reticuloendothelial system. Hemophagocytosis in the ascitic fluid has rarely been reported in HLH.

Sarcomas of the mediastinum with epithelioid morphology.

While soft tissue sarcomas typically have a spindled or pleomorphic appearance, a subset of malignant soft tissue neoplasms can have a prominent epithelioid morphology. In complex anatomic sites such as the mediastinum, such tumors can often be mistaken for a carcinoma or mesothelioma. Frequent expression of cytokeratin staining can further confound the diagnostic process and familiarity with these entities can help prevent an erroneous diagnosis.

Rhabdomyosarcoma with epithelioid morphology: A challenging cytologic diagnosis in a pleural effusion.

Rhabdomyosarcomas (RMS) are rare malignant skeletal muscle tumors that present more commonly in pediatric populations. The WHO currently classifies RMS into four types, embryonal, alveolar, pleomorphic, and spindle cell/sclerosing variants. Epithelioid rhabdomyosarcoma (EpiRMS) is another rare, recently described subtype of RMS presenting in older patients with a male predominance and has a rapidly progressive clinical course with frequent metastases.

"Inflammatory Leiomyosarcoma" and "Histiocyte-rich Rhabdomyoblastic Tumor": a clinicopathological, immunohistochemical and genetic study of 13 cases, with a proposal for reclassification as "Inflammatory Rhabdomyoblastic Tumor".

Inflammatory leiomyosarcoma (ILMS), defined as "a malignant neoplasm showing smooth muscle differentiation, a prominent inflammatory infiltrate, and near-haploidization", is a very rare soft tissue tumor with a generally favorable prognosis. The morphologic features of "histiocyte-rich rhabdomyoblastic tumor" (HRRMT) are similar to those of ILMS, although this lesion shows by definition a skeletal muscle phenotype. Recent gene expression profiling and immunohistochemical studies have also suggested that ILMS and HRRMT may be related.

A Novel Rearrangement in Cranial Fasciitis.

Cranial fasciitis is an uncommon benign fibroblastic tumor, generally histologically identical to nodular fasciitis. It develops almost exclusively in children. Cranial fasciitis manifests clinically as a painless rapidly growing solitary nodule in the head and neck area, frequently eroding the underlying bone.

Atypical Lipomatous Tumor/Well-Differentiated Liposarcoma With Features Mimicking Spindle Cell Lipoma.

Atypical lipomatous tumor/well-differentiated liposarcoma (ALT/WDL) and spindle cell lipoma are lipomatous tumors with distinct clinical, molecular, and prognostic features. Although histological and immunophenotypic features can overlap between ALT/WDL and spindle cell lipoma, the oncogenesis and clinical behavior are markedly different. In borderline cases, molecular analysis for or amplification can aid in distinguishing ALT/WDL from spindle cell lipoma.

Immunohistochemical characteristics of renomedullary interstitial cell tumor: a study of 41 tumors with emphasis on differential diagnosis of mesenchymal neoplasms.

Renomedullary interstitial cell tumors (RMICTs) are almost always incidentally identified either at autopsy or upon resection of the kidney for other reasons. However, rare cases that are large, resulting in a clinical mass, have been reported. The immunohistochemical phenotype of usual, incidental RMICT using modern soft tissue tumor markers is largely unknown, however, providing little information to aid in classification of larger or atypical tumors.

Pseudosarcomatous myofibroblastic proliferations of the genitourinary tract are genetically different from nodular fasciitis and lack USP6, ROS1 and ETV6 gene rearrangements.

Aims: Pseudosarcomatous myofibroblastic proliferations of the genitourinary tract have a debatable relationship with inflammatory myofibroblastic tumour (generally lacking ALK rearrangement); however, they share several overlapping features with nodular fasciitis of soft tissue. As rearrangement of the USP6 gene has been recently recognised as a recurrent alteration in soft tissue nodular fasciitis, and several other alternative gene fusions have been recently recognised in inflammatory myofibroblastic tumour, the aim of this study was to investigate whether USP6, ROS1 or ETV6 rearrangements were present in these lesions (12 cases).

Methods And Results: Fluorescence in-situ hybridisation analysis was performed by the use of bacterial artificial chromosome-derived break-apart probes against USP6, ROS1, and ETV6.

Composite hemangioendothelioma with neuroendocrine marker expression: an aggressive variant.

This corrects the article DOI: 10.1038/modpathol.2017.

Composite hemangioendothelioma with neuroendocrine marker expression: an aggressive variant.

Aberrant expression of neuroendocrine markers is extremely rare in endothelial neoplasms, with only a single report describing three cases. Although originally classified as conventional angiosarcoma, further assessment of these tumors revealed a strikingly composite morphology composed of retiform and epithelioid elements reminiscent of composite hemangioendothelioma, a rare subtype of hemangioendothelioma. To further investigate these findings, available materials from 11 morphologically distinctive endothelial tumors showing neuroendocrine marker expression were retrieved from our archives.

Endoscopic ultrasound-guided pancreatic fine-needle aspiration: potential pitfalls in one institution's experience of 1212 procedures.

Background: Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) has emerged as the diagnostic modality of choice for mass lesions in the pancreas. The objective of the current study was to determine the accuracy and pitfalls of EUS-FNA in the diagnosis of pancreatic lesions in cases that involved follow-up surgical resection.

Methods: Cases of EUS-FNA of pancreatic lesions performed from 2007 to mid-2012 for which subsequent surgical resection was performed were retrieved from the department's database.

Dyshormonogenetic goiter-like changes in a child with congenital hypothyroidism and a euthyroid adult.

Dyshormonogenetic goiter is a rare entity that presents in patients who typically have a history of congenital hypothyroidism, and generally arises from a genetic mutation compromising the production of functional thyroxine or thyroglobulin. Clinically, physical manifestations of goiter can result if left untreated. Histologically, the thyroid lesions usually show prominent bridging fibrosis, multiple thyroid nodules with different architectures, microfollicular arrangement, scant colloid, and enlarged vesicular or hyperchromatic nuclei.

Metastatic neuroendocrine tumour in the breast: a potential mimic of in-situ and invasive mammary carcinoma.

Aims: The aim of this study was to review the clinicopathological characteristics of neuroendocrine tumours (NETs) metastasizing to the breast, in order to identify features that could be useful in distinguishing these metastatic lesions from primary breast neoplasms.

Methods And Results: Eighteen metastatic NETs in the breast were identified from two large hospitals over a 15-year period. Eleven (62%) tumours originated in the gastrointestinal tract, 5 (28%) originated in the lung, and the other two were of indeterminate origin.

Ciliated cells in abdominal or pelvic fine needle aspirations: a case report and review of the literature.

Ciliated cells encountered outside of an expected anatomical location (e.g., the respiratory tract, fallopian tube, etc) can represent a diagnostic difficulty for the cytopathologist, especially during preliminary assessment of a fine needle aspiration (FNA) for adequacy or malignancy.

Alveolar rhabdomyosarcoma of the head and neck region in older adults: genetic characterization and a review of the literature.

Alveolar rhabdomyosarcoma is remarkably rare in adults older than 45 years. Initial immunoprofiling of a small cell neoplasm of the head and neck region in an older adult may not include myogenic markers. A valuable diagnostic aid and important prognostic parameter in alveolar rhabdomyosarcoma is the identification of PAX3-FOXO1 [t(2;13)(q35;q14)] or PAX7-FOXO1 [t(1;13)(p36;q14)] rearrangements.

Addition of rituximab to standard chemotherapy improves the survival of both the germinal center B-cell-like and non-germinal center B-cell-like subtypes of diffuse large B-cell lymphoma.

Purpose: Diffuse large B-cell lymphoma (DLBCL) includes at least two prognostically important subtypes (ie, germinal center B-cell-like [GCB] and activated B-cell-like [ABC] DLBCL), which initially were characterized by gene expression profiling and subsequently were confirmed by immunostaining. However, with the addition of rituximab to standard chemotherapy, the prognostic significance of this subclassification of DLBCL is unclear.

Patients And Methods: We studied 243 patient cases of de novo DLBCL, which included 131 patient cases treated with rituximab plus standard chemotherapy (rituximab group) and 112 patient cases treated with only standard chemotherapy (control group).