Extraskeletal myxoid chondrosarcoma: combining cytopathology with molecular testing to achieve diagnostic accuracy

Soft Tissue Fine-Needle Aspiration: Current and Future Impact on Patient Care

Soft tissue neoplasms pose many diagnostic challenges on fine-needle aspiration (FNA), owing largely to their rarity, large number of entities, and histologic diversity. Advances in ancillary testing now allow detection of the characteristic immunophenotypes and molecular alterations for many neoplasms and include reliable surrogate immunohistochemical markers for underlying molecular events that are highly efficient in small biopsies. A morphology-based framework is recommended to guide appropriate differentials and judicious selection of ancillary tests for small biopsies. The accurate diagnosis of soft tissue tumors is crucial for patient management and prognostication, with many potential implications in this era of precision medicine.

Myxoid Soft Tissue Tumors: A 20-Year Experience on Fine Needle Aspiration with Application of the Proposed WHO Reporting System for Soft Tissue Cytopathology

INTRODUCTION

Myxoid soft tissue tumors represent a heterogenous group of neoplasms. The study presented our experience on cytopathology of myxoid soft tissue tumors on fine needle aspiration (FNA) and aimed to apply the recently proposed WHO system for reporting soft tissue cytopathology.

MATERIAL AND METHODS

We performed a 20-year retrospective search of our archives to identify all FNAs performed on myxoid soft tissue lesions. All cases were reviewed, and the WHO reporting system was applied.

RESULTS

129 FNAs performed in 121 patients (62 males; 59 females) showed a prominent myxoid component, accounting for 2.4% of all soft tissue FNAs. The FNAs were performed on 111 (86.7%) primary tumors, 17 (13.2%) recurrent tumors, and one (0.8%) metastatic lesion. A spectrum of non-neoplastic and neoplastic lesions including both benign and malignant neoplasms was identified. Overall, the most common tumors identified were myxoid liposarcoma (27.1%), intramuscular myxoma (15.5%), and myxofibrosarcoma (13.1%). The sensitivity and specificity of FNA regarding the nature of the lesion (benign vs. malignant) were 98% and 100%, respectively. When the WHO reporting system was applied, the frequency of the categories was as follows: benign (7.8%), atypical (34.1%), soft tissue neoplasm of uncertain malignant potential (18.6%), suspicious for malignancy (3.1%), and malignant (36.4%). The risk of malignancy calculated in each category was as follows: benign (10%), atypical (31.8%), soft tissue neoplasm of uncertain malignant potential (50%), suspicious for malignancy (100%), and malignant (100%).

CONCLUSION

A diverse group of non-neoplastic and neoplastic lesions can show a prominent myxoid component on FNA. The WHO reporting system for soft tissue cytopathology is easily applicable and appears to correlate well with the malignant potential of myxoid tumors.

Chordoma: analysis of 47 fine-needle aspiration biopsy, cytologic imprint, and small biopsy specimens

INTRODUCTION

Fine-needle aspiration (FNA) and small tissue biopsy of chordoma have been reported in several small series, but no large series exists. We undertook an examination of 47 cases (with concurrent core needle biopsy in a subset) to analyze diagnostic accuracy, cytomorphology, and immunohistochemistry.

MATERIALS AND METHODS

Our cytopathology files were searched for examples of chordoma with histopathologic verification. FNA biopsy smears and core needle were performed using standard techniques.

RESULTS

Forty-seven cases of chordoma were retrieved from 44 patients [M:F; 1.8:1; age range 5-81 years; mean age 55 years]. Twenty-seven presented with primary, 10 with locally recurrent, and 7 with metastatic tumors. Two aspirates were from the appendicular skeleton, 2 from the trunk, 1 from neck lymph node, and 42 aspirates (89%) from axial and peri-axial skeleton and surrounding soft tissues. Four were cytologic touch imprints while the remainder were FNA biopsy specimens. Specific cytologic diagnoses were chordoma/consistent with chordoma (44 cases, 94%), suspicious for chordoma (2), and malignant neoplasm (1). Along with a single case of benign notochordal tumor misdiagnosed as chordoma, our diagnostic accuracy was 91%. Concurrent tissue biopsy was performed in 51% of cases. Immunohistochemical staining of tumor in 29 (62%) cases showed expression of brachyury in 23 of 24 (96%) instances. Cytopathology consisted of cellular smears populated by large cells possessing enormous amounts of vacuolated and non-vacuolated cytoplasm with an abundant background myxoid/chondromyxoid stroma.

CONCLUSIONS

FNA and small tissue biopsy specimens show a very high degree of diagnostic accuracy in recognition of chordoma.

Molecular testing of soft tissue tumors

BACKGROUND

The diagnosis of soft tissue tumors is challenging, especially when the evaluable material procured is limited. As a result, diagnostic ancillary testing is frequently needed. Moreover, there is a trend in soft tissue pathology toward increasing use of molecular results for tumor classification and prognostication. Hence, diagnosing newer tumor entities such as CIC-rearranged sarcoma explicitly requires molecular testing. Molecular testing can be accomplished by in situ hybridization, polymerase chain reaction, as well as next generation sequencing, and more recently such testing can even be accomplished leveraging an immunohistochemical proxy.

CONCLUSION

This review evaluates the role of different molecular tests in characterizing soft tissue tumors belonging to various cytomorphologic categories that have been sampled by small biopsy and cytologic techniques.

Approach to FNA of Myxoid Soft Tissue Tumors

Myxoid tumors of the soft tissue encompass a group of heterogenous tumors that are characterized by the presence of abundant extracellular myxoid or chondromyxoid matrix material. Fine needle aspiration (FNA) is variably used for diagnosing primary, recurrent, and metastatic myxoid soft tissue tumors. The spectrum of myxoid soft tissue tumors encountered in practice ranges from benign lesions such as simple ganglion cysts to high-grade malignant sarcomas such as myxofibrosarcoma. These myxoid tumors have clinical, cytologic, and histologic overlap. Therefore, making an accurate diagnosis by FNA alone is challenging. Despite this challenge, using a systematic cytomorphologic approach and ancillary studies, an accurate diagnosis is feasible in the majority of cases. This article provides a systematic approach to diagnosing myxoid soft tissue tumors by FNA along with a review of the literature.

Fine-needle aspiration cytopathology of soft tissue myoepithelioma: an analysis of seven cases

INTRODUCTION

Soft tissue myoepithelioma (STM), a rare mesenchymal neoplasm morphologically analogous to its more common salivary gland (SG) counterpart, is the subject of single case reports regarding its fine-needle aspiration (FNA) biopsy. To our knowledge, ours is the first case series of STM.

MATERIALS AND METHODS

A search was made of our pathology databases for cases diagnosed as STM. FNA biopsy smears and cell blocks were performed using standard techniques.

RESULTS

Seven cases were retrieved from 4 men and 3 women (M:F = 1.3:1; age range: 25-79 years, x = 54 years). All but 1 presented as a primary neoplasm. Six aspirates were from the extremities, and 1 from the abdominal wall. Mean tumor size was 5.7 cm. Cytologic diagnosis of STM or suspicious for STM was made in 3 cases (43%). Remaining FNA diagnoses were spindle cell neoplasm/lesion (2), spindle cell sarcoma (1), and extraskeletal myxoid chondrosarcoma (1). Three cases were composed primarily or solely of uniform spindle cells, 3 primarily of uniform epithelioid cells with plasmacytoid features, and 1 case a mixture of these 2 cell types. Myxoid/chondromyxoid stroma was relatively abundant except in the single hypocellular example. Immunohistochemical (IHC) testing performed in 71% was nonspecific, but positive with S-100 in 4 of 5, EMA in 3 of 3, calponin in 2 of 2, and keratin in 1 of 3 examples.

CONCLUSION

FNA biopsy smears of STM are remarkably similar cytomorphologically to their SG equivalent. However, STM can be misidentified principally as extraskeletal myxoid chondrosarcoma, thus requiring a relatively broad IHC panel for a specific diagnosis.

Extraskeletal myxoid chondrosarcoma: a case report with adjuvant intraoperative treatment

Extraskeletal myxoid chondrosarcoma is a rare form of malignant mesenchymal neoplasm mainly localized into the limbs, particularly in the thigh and popliteal fossa. It has been classified as a low-grade sarcoma so far, but it shows a tendency to relapse and metastasize. In the early stage of disease, surgery represents the only chance of cure. In case of diffuse metastatic disease, systemic chemotherapy with anthracyclines is the standard of care. In this paper, we present a case of a patient affected by this rare disease and the analysis of radiological, surgical and histopathological aspects.