Fine-needle aspiration in myxofibrosarcoma: Experience of Institut Curie

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.

Approach to Fine Needle Aspiration of Giant Cell-rich Tumors of Soft Tissue

Giant cells may be found in a wide variety of reactive and neoplastic soft tissue lesions. Because of their distinct histomorphology, they often stand out in procured samples such as fine needle aspirates. The giant cells themselves may be benign or neoplastic. However, the presence, type, and quantity of giant cells are usually not specific and in some cases can even be misleading when making a diagnosis. The aim of this review is to guide the practicing cytopathologist in narrowing their differential diagnosis when encountering one of these challenging giant cell-rich lesions of the soft tissue.

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.

Cytopathology of myxofibrosarcoma: a study of 66 cases and literature review

INTRODUCTION

Myxofibrosarcoma is one of the more common sarcomas encountered in adults.

MATERIALS AND METHODS

A search was made of our cytopathology and surgical pathology databases for cases diagnosed as myxofibrosarcoma (MyxoFS). FNA biopsy smears and cell block were performed and examined using standard techniques.

RESULTS

Sixty-six cases were retrieved from patients aged 40 to 94 years (mean: 67 years), with a male:female ratio of 1.4:1. Forty-seven (71%) were primary neoplasms, 13 (20%) locally recurrent, and 6 (9%) metastasis. Lower extremity was the most common site 38 (58%) cases, followed by upper extremity and trunk (each 13 [20%] cases), 1 head/neck, and 1 pleural-based mass. Forty-two (64%) cases were specifically/correctly diagnosed as MyxoFS. Thirteen (20%) were diagnosed as undifferentiated pleomorphic sarcoma (UPS), 3 (4.5%) as myxoid neoplasm, 2 (3%) as myxoid sarcoma, and 1 (1.5%) sarcoma, not otherwise specified. As most were examples of high-grade (HG) MyxoFS, cytomorphology contained pleomorphic and spindled cells set in a variable amount of myxoid stroma. Arborizing capillaries were common, and pseudolipoblasts were uncommon. All cases interpreted as UPS were HG MyxoFS histologically. Five (7.5%) cases-pleomorphic liposarcoma (3), solitary fibrous tumor (1), and atypical lipoma (1)-were mistakenly diagnosed. Ancillary immunohistochemistry played a minor role in diagnostic assessment.

CONCLUSION

MyxoFS was accurately interpreted using FNA biopsy in about two thirds of cases. One fifth were misinterpreted as UPS due to the absence/near absence of myxoid stroma, which varies considerably in the definition of this neoplasm.

Fine needle aspiration of malignant melanoma with myxoid features: A case report with molecular analysis

Malignant melanoma with myxoid features (MMM) is a rare melanoma variant in which tumor cells are embedded within a basophilic myxoid stroma. The stromal matrix is composed of acidic mucopolysaccharides, which are thought to be produced by mesenchymal stromal cells in response to melanoma invasion. Interestingly, this myxoid matrix is more often seen in metastasis from a primary tumor that does not have a myxoid stroma. The diagnosis of MMM on fine needle aspiration (FNA) can be confused with other myxoid tumors. Herein, we present a case of MMM diagnosed by FNA of a peri-auricular lymph node in an 89-year-old man with a history of resected malignant melanoma. We describe the clinical, cytohistological, and immunohistochemical findings, and present the unique molecular alterations that were identified. We also discuss the differential diagnosis and potential diagnostic pitfalls associated with MMM.

Soft tissue tumor diagnosis: A three prong approach utilizing pattern analysis, immunocytochemistry, and molecular diagnostics

Tissue diagnosis of a soft tissue neoplasm is of paramount importance for the development of an appropriate treatment plan. Biopsy technique including approach and biopsy method is important to the success of diagnosis and subsequent treatment. Histologic and cytologic diagnoses are difficult and complicated by the large number of soft tissue lesions described, distinctly different biopotential for morphologically similar lesions, often small biopsy specimen size, and the generally limited experience many pathologists have in the diagnosis of soft tissue neoplasms. While utilized less frequently than core-needle biopsies, fine-needle aspiration is a valuable initial approach for the classification of soft tissue neoplasms. The combination of pattern based morphologic analysis, immunohistochemistry, and molecular diagnostics represents a utilitarian and generally successful approach for the diagnosis of soft tissue lesions.

Rare, risky, recurrent: An enigmatic cutaneous polyp

Myxofibrosarcomas (MFSs) are sarcomas most commonly seen in older patients. These are tumors of deep soft tissue seen in subcutaneous tissue and deep fascia, with frequent muscle involvement. These sarcomas are notorious for recurrences and progression to a higher grade with notable metastatic potential. They are very often under-diagnosed owing to their inherent morphological variability. A case of MFS is presented as a cutaneous, exophytic, polypoidal mass because of its rarity and importance of timely diagnosis, as under-diagnosis may lead to inadequate clearance of tumor, recurrences, metastases and increased mortality.

Applications of Ancillary Testing in the Cytologic Diagnosis of Soft Tissue Neoplasms

Soft tissue neoplasms are diagnostically challenging, although many advances in ancillary testing now enable accurate classification of fine-needle aspiration biopsies by detection of characteristic immunophenotypes (including protein correlates of molecular alterations) and molecular features. Although there are many useful diagnostic immunohistochemical markers and molecular assays, their diagnostic utility relies on correlation with clinical and morphologic features, judicious application, and appropriate interpretation because no single test is perfectly sensitive or specific. This review discusses applications of ancillary testing for commonly encountered soft tissue neoplasms in cytopathologic practice in the context of a pattern-based approach.

Hypercellular round cell liposarcoma: A comprehensive cytomorphologic study and review of 8 cases

Background:

Myxoid and round cell liposarcomas (RCL) are low and high-grade counterparts of a common subtype of liposarcomas (LPS), representing a histologic continuum.

Aims:

The aim was to study the cytomorphology of hypercellular RCL and to look for features that differentiate RCL from other sarcomas displaying round cells with myxoid change.

Materials and Methods:

Eight cases of hypercellular RCL were identified retrospectively in which round cell component constituted greater than 75% of the area. Cytomorphological features were studied in detail.

Results:

Four cases were predominantly composed of round cells, out of which 2 were entirely composed of round cells. Myxoid metachromatic stroma was absent in 2 cases, while it was present in ample amounts in the remaining 6 cases. Spindle cells were completely absent in 5 cases and lipoblasts were observed in a single case of RCL. Plexiform vascular capillaries were seen in 4 cases. Adherence of neoplastic round cells around thin capillaries (ANAC) was observed in 7 cases.

Conclusions:

Plexiform capillary plexus and ANAC should be separately evaluated. The latter feature is the most consistent one, and is an important clue to the adipocytic nature of the neoplasm when hypercellular round cell areas are aspirated. Confident diagnosis of hypercellular RCL can be made on the basis of this feature. Lipoblasts, although specific, are seen in few cases. The rest of the features are nonspecific and useful only in combination.

[Cytologic diagnosis of sarcoma]

Soft tissue swelling represents a common clinical sign of a variety of neoplastic and non-neoplastic lesions. Sarcoma is rarely a cause. Fine needle biopsy as a minimally invasive, economic and accurate method is well suited for the diagnosis of inflammatory/infectious processes as well as of recurrent and metastatic disease. Cytologic diagnosis of primary soft tissue tumors is also feasible. It requires close collaboration with other medical disciplines and incorporation of clinical, radiological and morphologic findings. Clinical data such as age, gender, size and topography are important parameters. The differentiation of cells and properties of the extracellular matrix supplies clues for the differential diagnosis and forms the starting point for immunohistochemical or molecular analysis (FISH, RT-PCR). This analysis may be performed on cytological smears, paraffin embedded material of the cell blocks or on frozen material.