FNA of extraskeletal myxoid chondrosarcoma: cytomorphologic, EM, and X-ray microanalysis features

Dynamic niches in the origination and differentiation of haematopoietic stem cells

Haematopoietic stem cells (HSCs) are multipotent, self-renewing progenitors that generate all mature blood cells. HSC function is tightly controlled to maintain haematopoietic homeostasis, and this regulation relies on specialized cells and factors that constitute the haematopoietic 'niche', or microenvironment. Recent discoveries, aided in part by technological advances in in vivo imaging, have engendered a new appreciation for the dynamic nature of the niche, identifying novel cellular and acellular niche components and uncovering fluctuations in the relative importance of these components over time. These new insights significantly improve our understanding of haematopoiesis and raise fundamental questions about what truly constitutes a stem cell niche.

Cytopathology of extraskeletal myxoid chondrosarcoma

BACKGROUND

Extraskeletal myxoid chondrosarcoma (EMC) is a rare soft-tissue sarcoma rarely subjected to cytologic analysis. With the exception of a few small series, the cytology literature of EMC is largely limited to single-case reports. The purpose was to evaluate the cytomorphology of 8 EMC cases as obtained by imprint/scrape cytology and fine-needle aspiration (FNA) biopsy, to review the literature, and to demonstrate the utility of cytogenetic analysis in the diagnosis of EMC.

METHODS

The cytology files were reviewed for all soft-tissue lesions signed out as chondrosarcoma, myxoid sarcoma, and EMC, and the tissue files for any cases of EMC that had corresponding cytopathology. FNA was performed using a standard technique. Scrape preparations were performed from tissue sent fresh to the laboratory for either frozen section or for special studies such as electron microscopy or tissue banking.

RESULTS

Eight cases of EMC were retrieved from 4 men and 3 women (median age = 62 years). One patient had 2 separate cytologic specimens 4.5 years apart. All patients had subsequent tissue confirmation of the diagnosis of EMC. Five individuals presented as new patients, and 2 had a prior diagnosis of EMC. Sites included 4 masses from the foot/ankle, 2 from the calf, 1 wrist mass, and 1 buttock mass. Five patients were diagnosed from FNA biopsy, whereas 3 were diagnosed using scrape slides. Five cases were correctly and categorically diagnosed by the cytologic method as EMC, 1 as chondrosarcoma favor EMC, 1 as sarcoma favor EMC, and 1 as myxoid spindle/epithelial neoplasm. Cytologic features ranged from hypocellular to highly cellular smears composed primarily of rounded cells set in an abundant myxoid stroma that varied from opaque to semitransparent and lacked vascularity or necrosis. Smears showed cells in short, sometimes anastomosing cords, but also as single cells and nondescript cell clusters. Cells displayed a monotonous uniformity in nuclear diameter and cell size. Bland nuclei with evenly dispersed chromatin displayed variably sized nucleoli, and a moderate amount of infrequently vacuolated cytoplasm. Tissue fragments of variable size were found in 5 of 5 FNA cell blocks. Fluorescence in situ hybridization (FISH) analysis using the EWSR1 probe showed a positive 22q12 translocation in 2 of 3 FNA cases that were tested. One case with negative FISH results on the cytologic preparation showed a positive translocation using the same technique in the subsequent resection specimen.

CONCLUSIONS

A confident cytologic diagnosis of EMC depends on the presence of a uniform, round to oval cell population often arranged in cords and set in an abundant myxoid/chondromyxoid background and arising in the appropriate clinical context. If positive, FISH testing (of paraffin cell blocks or cytospin preparations) is confirmatory when coupled with this cytomorphology.

Myxoid chondrosarcoma of the sphenoid sinus and chondromyxoid fibroma of the iliac bone: cytomorphologic findings of two distinct and uncommon myxoid lesions

Myxoid chondrosarcoma (MCS) and chondromyxoid fibroma (CMF) are two uncommon myxoid cartilaginous neoplasms with distinct cytologic features, histologic patterns, and immunoprofiles. Because these neoplasms have characteristic biological behaviors and management, their correct diagnosis is crucial to avoid debilitating and unnecessary surgical procedures. We report the imprint cytology (IC) preparation findings along with the differential diagnosis in one case each of myxoid chondrosarcoma and chondromyxoid fibroma of the splenoid sinus and iliac bone, respectively. The two great mimickers for these neoplasms, chordoma and chondrosarcoma, represent difficult diagnostic challenges, especially when MCS and CMF occur in unusual locations. IC in conjunction with the clinical and radiologic findings can provide a rapid preliminary intraoperative diagnostic interpretation which can aid in planning the immediate surgical management, as well as guide specific tissue triage for key ancillary studies such as electron microscopy and cytogenetic analyses. To the best of our knowledge, there have been no cytologic reports of MCS of the sphenoid sinus and CMF of the iliac bone.

Myxomatous soft tissue tumors: correlation of cytopathology and histopathology

A small, uncommon group of soft tissue tumors are distinguished by their unique and consistent ability to produce an overwhelming abundance of myxoid ground substance along with the proliferating cells that constitute the tumor. Grossly, all these neoplasms have a variable gelatinous quality. Because of the voluminous stroma, most of these tumors have some findings that overlap with one another. Nonetheless, each tumor has a composite set of morphologic, immunophenotypic, ultrastructural, and genotypic features exclusive to itself. Because soft tissue masses are not a frequent site of fine-needle aspiration, the cytopathology of this set of tumors is vastly unappreciated, both in the literature and in day-to-day practice. The aim of this review is to detail the salient light microscopic findings of this group of six major myxoid soft tissue tumors, to correlate the cytopathology (particularly as obtained using the fine-needle aspiration biopsy technique) with its histopathologic counterparts, and to discuss the limitations of both cytologic and histologic methods. This cytohistopathologic correlation should assist the reader in the diagnosis of myxoid tumors of soft tissue.

Atypical chondroma of the cricoid cartilage: fine-needle aspiration cytologic and histopathologic findings

Chondroma of the laryngeal skeleton is a rare, benign neoplasm manifested either as a neck mass or, if situated within the airway, as slowly progressive obstruction, hoarseness, or dyspnea. The most common site is the posterior plate of the cricoid cartilage. An atypical perichondrial chondroma arising from the anterior plate of the cricoid cartilage membrane as a neck mass in a young female is presented. The diagnosis was made on a fine-needle aspiration of the mass and subsequently confirmed by histologic examination of the excised mass. Although rare, cartilaginous tumors of the laryngeal skeleton can manifest as a neck mass, and the diagnosis can be made by fine-needle aspiration biopsy in combination with radiographic and clinical examinations. Therefore, the existence and inclusion of these tumors in the differential diagnosis of neck masses by aspiration biopsy should be considered by clinicians and pathologists, and especially cytopathologists, when cartilaginous components are encountered.

Logistic regression analysis of myxoid sarcomas: a cytologic study

The objective of this study was to identify key diagnostic cytologic criteria for the most common myxoid sarcomas studied by fine-needle aspiration cytology. We reviewed 27 myxoid malignant fibrous histiocytomas, 8 chordomas, 16 chondrosarcomas, and 12 myxoid liposarcomas in which both cytologic specimens and final histopathologic diagnoses were available. All specimens were coded as to the presence or absence of the following variables: high cellularity, low cellularity, tissue fragments, epithelial fragments, pale/loose ground substance, dense ground substance, chondroid fragments, large amount of myxoid material, small amount of myxoid material, capillary vessel networks, pleomorphism, binucleate cells, multinucleate cells, physaliphorous cells, cells in lacunae, signet ring cells, lipoblasts, fibroblast-like cells, histiocyte-like cells, stellate cells, long filamentous cells, short spindle cells, osteoclastic giant cells, nuclei with pointed ends, nuclei with cigar-shaped ends, fish-hook nuclei, round/ovoid nuclei, naked nuclei, large nucleoli, small nucleoli, mitotic figures, abnormal mitotic figures, intracytoplasmic hemosiderin deposits, background cells, fat, cytoplasmic vacuoles, and pleomorphic giant cells. A logistic regression analysis was performed to identify the variables predictive of myxoid malignant fibrous histiocytoma, chordoma, myxoid chondrosarcoma, and myxoid liposarcoma. The statistical analysis selected pleomorphic giant cells and the presence of fibroblast-like cells as most predictive of malignant fibrous histiocytoma, physaliphorous cells as most closely associated with chordoma, chondroid fragments as most predictive of chondrosarcoma, and lipoblasts as most predictive of liposarcoma. While myxoid lesions have many overlapping cytologic features, key criteria including the presence of lipoblasts, physaliphorous cells, chondroid fragments, and pleomorphic giant cells are useful in subclassifying these neoplasms.