The fine needle aspiration of translocation sarcomas

Myxoid neoplasms of bone and soft tissue: a pattern-based approach

INTRODUCTION

The accurate diagnosis of musculoskeletal neoplasms is difficult but a pattern-based approach combined with ancillary testing has been shown to improve diagnostic accuracy. The pattern-based approach is particularly appropriate for myxoid lesions.

MATERIALS AND METHODS

The authors reviewed their personal experience of over 3 decades of diagnosing myxoid neoplasms of musculoskeletal lesions.

RESULTS

The authors found that myxoid lesions can be accurately classified based on cell type, nuclear atypia, presence of blood vessel fragments, as well as the results of immunohistochemical and molecular testing.

CONCLUSIONS

Musculoskeletal lesions with a prominence of myxoid or chondroid material in the background can be accurately diagnosed using pattern analysis and ancillary testing.

Alveolar rhabdomyosarcomas involving serous cavity fluid specimens exhibit diverse cytomorphologies: A case report and review of the literature

Involvement of serous cavity specimens by alveolar rhabdomyosarcoma (ARMS) is a rare event and only a few case reports have been reported in the literature, with conflicting cytomorphologic patterns. Herein, we report on a 41-year-old man with no significant past medical history who presented with pancytopenia and shortness of breath and was found to have widely metastatic sinonasal alveolar rhabdomyosarcoma, including involvement of the pleura. The pleural fluid specimen was cellular and contained ARMS cells in small-to-medium sized three-dimensional fragments that resembled an adenocarcinoma or mesothelioma, and numerous single cells were seen in the background. The individual tumor cells demonstrated variable morphology; all were large, with varying degree of cytoplasm, and multinucleated cells were commonly seen in the background. The cells were negative for calretinin and claudin-4 and were positive for myogenin, confirming the diagnosis. Given the cytomorphologic diversity of ARMS seen in serous fluid specimens, patient history and the use of confirmatory immunostains are essential.

A comprehensive diagnosis of a desmoplastic small round cell tumor of unusual location based on fine-needle aspiration cytology: Report of a case arising in the parotid gland and review of the literature

Desmoplastic small round cell tumor (DSRCT) is rare and a highly aggressive neoplasm that typically involves the soft tissues of the abdomen or pelvis in children or young adults, showing a male predilection. Although it can occurs over a wide age range, the peak incidence is in the third decade of life. DSRCT usually shows widespread abdominal serosal involvement, and overall patient survival is poor. On the other hand, extra-abdominal DSRCT is very rare. DSRCT in major salivary glands has been reported, but it is extremely rare. In the majority of reported series diagnosis is made by the histological analysis of FFPE tissues together with immunohistochemistry (IHC) and molecular analysis, particularly the demonstration of chromosomal translocation involving EWSR1. Very few cases have been diagnosed so far by Fine Needle Aspiration (FNA) cytology. Moreover ancillary studies have been performed in all reported cases in FFPE samples. There is still controversy and lack of consensus regarding the suitability of cytological samples especially smears for immunocytochemical (ICC) and fluorescence in situ hybridization (FISH), what makes its standardization difficult. We report a case of a primary DSRCT of parotid gland in a 17-year-old male diagnosed by FNA cytology. The cytomorphological diagnosis was coupled with ICC and FISH analysis performed on stained smears. We emphasize the feasibility and reliability of cytological smears for the application of immunocytochemical and molecular techniques.

Cytomorphological spectrum, including immunohistochemical results of 16 cases of clear cell sarcoma of soft tissue, along with positive EWSR1 gene rearrangement result in two cases

OBJECTIVES

To describe the cytopathological features of clear cell sarcomas (CCSs), including immunohistochemical and molecular results, the latter in selected cases.

METHODS

Sixteen consecutively diagnosed cases of CCS of soft tissue, over 6-year duration were included. Fine needle aspiration cytology was performed for primary diagnosis in three and for recurrent/metastatic lesions in 12 cases. Cytopathological features in 16 cases (conventional Papanicolaou- and May-Grünwald Giemsa-stained smears) were critically analysed. Corresponding histopathological and immunostained sections were available in 15 cases. Two cases were tested for EWSR1 gene rearrangement by fluorescence in-situ hybridisation.

RESULTS

Sixteen tumours occurred in patients with age ranging from 18 to 56 years (median = 33.5); M: F ratio = 1:1; in deep soft tissues, mostly in extremities. Primary cytopathological diagnosis (3 cases) was CCS with a differential diagnosis of melanoma (1 case) and poorly differentiated malignant tumour (2 cases). On review, smears were predominantly hypercellular (n = 14), invariably composed of monomorphic appearing epithelioid/polygonal cells (n = 16), including spindle cells (n = 6); mostly singly scattered (n = 16), in loose clusters (n = 12); with prominent nucleolisation (n = 16); granular to vacuolated, well-defined cytoplasm (n = 12), binucleation/multinucleation (n = 9); mitoses (n = 6); sudden anisonucleosis; racquet-shaped cells (n = 3), against a tigroid background (n = 2), along with focal intracytoplasmic pigment deposition (n = 2). Immunohistochemically, tumour cells were positive for S-100P (15/15), HMB-45 (15/15) and melan-A(6/12). Two cases tested for EWSR1 rearrangement displayed red-green split signals.

CONCLUSIONS

This constitutes one of the largest series describing the cytomorphological spectrum of CCS of soft tissue. Certain features, such as singly scattered monomorphic, epithelioid cells with prominent nucleolisation are useful diagnostic clues. Immunohistochemical stains are necessary and molecular testing is further helpful in reinforcing a diagnosis in certain cases. A correct diagnosis has crucial treatment implications.

Cytomorphologic findings of low-grade fibromyxoid sarcoma

INTRODUCTION

Low-grade fibromyxoid sarcoma (LGFMS) is a rare fibroblastic tumor characterized by a prolonged clinical course and malignant biological behavior. Given its deceptively bland cytomorphology, a diagnosis can be quite challenging notably on fine-needle aspiration (FNA). In an attempt to shed light on some of the distinctive cytomorphologic characteristics, this study was conducted to review all cases of LGFMS in our database, correlating available clinical data, immunohistochemical findings, and molecular analysis.

MATERIALS AND METHODS

This series included 20 FNAs from 18 patients with a histologically confirmed LGFMS diagnosis from 3 large academic institutions. Detailed cytomorphologic analysis for each case was documented in conjunction with corresponding clinical characteristics and provided ancillary testing.

RESULTS

Out of 14 adequate FNA samples, 9 (64.2%) demonstrated a mixture of fibrous and myxoid pattern; the majority of cases were composed of deceptively bland tumor cells with rare nuclear pleomorphism and nuclear membrane irregularities. A MUC4 immunostain was performed on 5 specimens; all tested positive (100%). FUS rearrangement was detected in 4 out of 5 cases (80%). Follow-up information revealed 5-year recurrence in 1 case and metastatic disease in 2 cases, to the lung/pleura (8 years) and fourth rib (1 year), respectively.

CONCLUSIONS

The presence of bland spindle cells and associated with myxoid matrix material, in the appropriate clinical setting, can suggest LGFMS and direct additional confirmatory testing. A definitive diagnosis of LGFMS on FNA requires adequate sampling, familiarity with key cytomorphologic features, acquisition of diagnostic material for a cell block preparation and ancillary testing, and clinicoradiologic correlation.