Fine-needle aspiration in liposarcoma: Cytohistologic correlative study including well-differentiated, myxoid, and pleomorphic variants

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.

Diagnosing liposarcoma on (peri)-renal mass biopsy: A clinicopathological study of 30 cases

AIMS

Classification of renal neoplasms on small tissue biopsies is in increasing demand, and maintaining broad differential diagnostic considerations in this setting is necessary. When evaluating a renal or perirenal tumour biopsy with sarcomatoid morphology, together with sarcomatoid renal cell carcinoma and sarcomatoid urothelial carcinoma as top diagnostic considerations, it is vital to additionally consider the possibility of well-differentiated and de-differentiated liposarcoma.

METHODS AND RESULTS

This study reports a series of 30 biopsy samples from sites in or around the kidney collected from four institutions in which the correct diagnosis was either well-differentiated or de-differentiated liposarcoma. The majority (26 of 30, 87%) of lesions were accurately diagnosed on biopsy sampling, all of which incorporated testing for MDM2 by immunohistochemistry (IHC), fluorescence in-situ hybridisation (FISH) or a combination of the two as part of the diagnostic work-up. Tumour expression of MDM2 by IHC without confirmatory FISH analysis was sometimes (30%) sufficient to reach a diagnosis, but demonstration of MDM2 amplification by FISH was ascertained in the majority (57%) of biopsy samples. A diagnosis of de-differentiated liposarcoma was not definitively established until resection in four (13%) patients, as no MDM2 testing was performed on the corresponding pre-operative biopsies.

CONCLUSIONS

When a retroperitoneal tumour is not clinically suspected, histological consideration of a liposarcoma diagnosis may be overlooked. Implementation of ancillary immunohistochemical and cytogenetic testing can ultimately lead to a definitive diagnosis in this potentially misleading anatomical location.

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.

Annotation-Free Deep Learning-Based Prediction of Thyroid Molecular Cancer Biomarker BRAF (V600E) from Cytological Slides

Thyroid cancer is the most common endocrine cancer. Papillary thyroid cancer (PTC) is the most prevalent form of malignancy among all thyroid cancers arising from follicular cells. Fine needle aspiration cytology (FNAC) is a non-invasive method regarded as the most cost-effective and accurate diagnostic method of choice in diagnosing PTC. Identification of BRAF (V600E) mutation in thyroid neoplasia may be beneficial because it is specific for malignancy, implies a worse prognosis, and is the target for selective BRAF inhibitors. To the authors' best knowledge, this is the first automated precision oncology framework effectively predict BRAF (V600E) immunostaining result in thyroidectomy specimen directly from Papanicolaou-stained thyroid fine-needle aspiration cytology and ThinPrep cytological slides, which is helpful for novel targeted therapies and prognosis prediction. The proposed deep learning (DL) framework is evaluated on a dataset of 118 whole slide images. The results show that the proposed DL-based technique achieves an accuracy of 87%, a precision of 94%, a sensitivity of 91%, a specificity of 71% and a mean of sensitivity and specificity at 81% and outperformed three state-of-the-art deep learning approaches. This study demonstrates the feasibility of DL-based prediction of critical molecular features in cytological slides, which not only aid in accurate diagnosis but also provide useful information in guiding clinical decision-making in patients with thyroid cancer. With the accumulation of data and the continuous advancement of technology, the performance of DL systems is expected to be improved in the near future. Therefore, we expect that DL can provide a cost-effective and time-effective alternative tool for patients in the era of precision oncology.

Liposarcoma of the scalp mimicking a lipoma: a case report

Background

Liposarcomas are malignant tumours of adipocytic differentiation and their occurrence within the head and neck region is very uncommon. Lipomas are the most common types of benign mesenchymal tumours. The clinical, histological and imaging features of well-differentiated liposarcoma may resemble that of lipoma, causing challenges in the diagnosis. The management and prognosis of benign lipomas and well-differentiated liposarcoma are different.

Case presentation

A 73-year-old man presented with a painless soft mass in the left temporal region for 15 years with recent rapid growth. The scalp mass was clinically diagnosed as lipoma, while MRI suspected an atypical lipomatous lesion. Complete surgical resection was performed, and histopathological examination confirmed a well-differentiated liposarcoma.

The patient recovered completely and will be followed up with long-term surveillance.

Conclusion

This report is to highlight that clinicians must have a high index of suspicion for this rare entity when dealing with scalp masses and suspicious radiological findings, which can affect the overall management and prognosis.

Pleomorphic liposarcoma: A clinicopathologic study of 20 FNA cases

BACKGROUND

Pleomorphic liposarcoma (PLPS) is the least common but most aggressive of all forms of liposarcoma (LPS). Its diagnosis relies on the recognition of pleomorphic lipoblasts (PLBs), whose numbers vary considerably. Because few large fine-needle aspiration (FNA) biopsy studies exist, the authors review their experience with PLPS.

METHODS

The authors' cytopathology files were searched for PLPS with histopathologic verification. FNA biopsy smears were performed via standard techniques.

RESULTS

Twenty cases from 20 patients (male/female ratio, 2.3/1; age range, 22-77 years; mean age, 58 years) met the inclusion criteria. All had tissue confirmation. Biopsy sites included the following: thigh (11 [55%]), upper extremity (4 [20%]), axilla (2 [10%]), neck (1 [5%]), chest wall (1 [5%]), and mediastinum (1 [5%]). Aspirates were from primary (17 [85%]), locally recurrent (2 [10%]), and metastatic neoplasms (1 [5%]). The FNA diagnoses were PLPS (10 [50%]), myxofibrosarcoma (4 [20%]), LPS (2 [10%]), sarcoma (2 [10%]), and high-grade malignant neoplasm (2 [10%]). Smears showed thick cell clusters and dissociated single forms. Pleomorphic, epithelioid, and bizarre cell/nuclear shapes were common. PLBs were absent, rare, or unnoticed in 45%. In 25%, smears dominated by myxoid stroma were diagnosed as high-grade myxofibrosarcoma or myxoid LPS. Ancillary testing performed in 5 cases had limited diagnostic efficacy.

CONCLUSIONS

FNA biopsy of PLPS, although able to successfully recognize malignancy, suffers from a sampling bias due to an inability to capture or recognize PLBs in a significant proportion of cases secondary to the heterogeneous composition of this neoplasm.

Diagnostic Challenges in Fine-Needle Aspiration Cytology of Mediastinal Tumors and Lesions

CONTEXT.—

Mediastinal tumors/lesions are frequently encountered in daily cytopathology practice. These lesions are accessible through endoscopic/endobronchial ultrasound-guided or computed tomography-guided fine-needle aspiration cytology and represent a wide range of primary and metastatic tumors. This often poses diagnostic challenges because of the complexity of the mediastinal anatomic structures. Tumors metastatic to mediastinal lymph nodes represent the most common mediastinal lesions and must be differentiated from primary lesions.

OBJECTIVE.—

To provide an updated review on the fine-needle aspiration cytology of mediastinal tumors/lesions, with an emphasis on diagnostic challenges. This review encompasses thymic epithelial neoplasms, mediastinal lymphoproliferative disorders, germ cell tumors, neuroendocrine tumors, soft tissue tumors, and metastatic tumors. Differential diagnoses; useful ancillary studies, including targeted immunohistochemical panels; and diagnostic pitfalls are discussed.

DATA SOURCES.—

Data were gathered from a PubMed search of peer-reviewed literature on mediastinal tumors. Data were also collected from the authors' own practices.

CONCLUSIONS.—

Fine-needle aspiration cytology plays a vital role in evaluation of mediastinal lesions. Being familiar with the clinical and cytomorphologic features of these lesions, appropriately triaging the diagnostic material for ancillary testing, and correlating with radiologic findings are important in arriving at correct diagnoses and guiding management.

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.

Mediastinal sarcomas: experience using fine needle aspiration cytopathology

Fine needle aspiration (FNA) cytology is a sparsely used diagnostic method in the evaluation of mediastinal sarcomas in most medical centers worldwide with most literature citations regarding this category of malignancies consisting of small series and individual case reports. Most of these published studies highlight vascular sarcomas such as epithelioid hemangioendothelioma, and angiosarcoma, various subtypes of liposarcoma including well-differentiated liposarcoma, myxoid liposarcoma, and pleomorphic liposarcoma, malignant peripheral nerve sheath tumor, and sarcomas of uncertain differentiation, primary synovial sarcoma and the Ewing sarcoma family of tumors. This paucity of cytopathology reports regarding mediastinal sarcomas is in marked contrast to the almost daily application of endobronchial ultrasound (EBUS)-guided FNA biopsy for sampling mediastinal lymph nodes and mediastinal masses for primary and metastatic carcinomas which, of course, are considerably more common that any type of sarcoma in this location. EBUS, endoscopic ultrasound-guided (EUS) needle biopsy, and percutaneous image-guided biopsy using either core needle, fine-needle, or both can serve a potentially useful role for diagnostic sampling of mediastinal sarcomas, be they primary or metastatic. This review catalogues much of the published data regarding FNA cytopathology and its application to mediastinal sarcomas. An attempt is made to primarily highlight case series rather than individual case reports; however, due to the paucity of these, case reports are cited and discussed where appropriate.

Practical Application of Cytology and Core Biopsy in the Diagnosis of Mesenchymal Tumors

Soft tissue neoplasms are increasingly being sampled by core needle biopsy and fine-needle aspiration (FNA), and these small biopsy specimens pose unique diagnostic challenges. Many advances in ancillary testing enable detection of characteristic immunophenotypes and molecular alterations, allowing accurate classification of soft tissue tumors in these small biopsy samples. This review outlines pattern-based diagnostic approaches to core biopsies and FNAs of soft tissue neoplasms, including formulation of practical differential diagnoses and relevant application of ancillary tests.

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.

High-Grade Myxoid Liposarcoma (Round Cell Variant) in a Dog

A 10-year-old, neutered male, Basset hound had a 26 × 21 × 21 cm infiltrative mass on the left abdominal wall that did not extend into the peritoneal cavity based on radiographs and abdominal computed tomography. Cytological examination revealed moderate numbers of neoplastic round cells, which frequently contained numerous round, clear, cytoplasmic vacuoles. Histologically, the tumour was composed of two morphologically distinct cell populations forming a continuum of heterogeneously differentiated cells. The primary spindle-shaped population formed streams with abundant, lightly eosinophilic, alcian blue-positive, myxoid matrix. The second population was arranged in sheets and had a round cell appearance. Scattered within both populations were neoplastic cells containing variably sized, intracytoplasmic, osmium tetroxide-positive vacuoles (lipid). Multifocal large pools of mucin formed pseudocysts, and numerous small capillaries were present throughout the neoplasm. According to the current World Health Organization veterinary classification of liposarcomas, this neoplasm had morphological features of both the myxoid and pleomorphic variants of liposarcoma; however, it was analogous to the recently defined high-grade myxoid liposarcoma in man. Myxoid liposarcoma with round cells has not been described previously in dogs. This case highlights the need to potentially re-evaluate the current classification of liposarcomas in animals.

Myxoid liposarcoma: Fine-needle aspiration cytopathology in the molecular era. A report of 24 cases

INTRODUCTION

Application of fine-needle aspiration (FNA) biopsy to soft tissue tumors remains underutilized in North America. Myxoid liposarcoma (LPS), the second most common subtype of LPS, is characterized primarily by t(12;16)(q13;p11) which is amenable to FISH analysis using a break-apart probe for DDIT3. Little is known regarding FISH testing for DDIT3 on cytologic specimens. We report our FNA experience with myxoid LPS and application of this molecular probe.

MATERIALS AND METHODS

Specimens retrieved from our cytology database used search codes for myxoid LPS. Tissue files were searched for any cases with corresponding FNA biopsies. FNA biopsy was performed using a standard technique.

RESULTS

From 24 FNA cases of myxoid LPS (mean age = 52 years), a specific diagnosis was made in 87.5%. Two cases were diagnosed as spindle/round cell neoplasm, and 1 as suspicious for myxoid LPS. There were 2 false positive diagnoses and no false negatives. Nearly all cases arose in the extremities; thigh being most common. Principal cytologic features consisted of discrete myxocellular microfragments, a plexiform capillary pattern, and variable number of univacuolated lipoblasts. Uniformly banal ovoid nuclei were randomly scattered within myxocellular microfragments. FISH analysis for DDIT3 rearrangement from unstained smears and/or cell-block was positive in 13 cases, and unsuccessful in 3, with no false positive/false negative results.

CONCLUSION

Myxoid LPS is diagnosable in a high percentage of cases using FNA biopsy alone. Confirmatory FISH analysis for DDIT3 is not only possible, but also valuable for correctly recognizing this neoplasm.

Pleomorphic liposarcoma: a cytologic study of five cases

Pleomorphic liposarcoma represents one of the rarest variants of liposarcoma. It has a poor prognosis and unlike other variants of liposarcoma, lacks a molecular or genetic signature. Histologic studies of pleomorphic liposarcoma have defined this lesion as a high grade sarcoma, which contains a variable number of lipoblasts. We describe the cytologic features of five cases of pleomorphic liposarcoma, all of which had histologic confirmation. We consistently identified numerous lipoblasts as well as micro and macrovesicular fat vacuoles in the background of cellular, pleomorphic sarcomatoid neoplasms. The appearance of the aspirates differs substantially form other variants of liposarcoma.

Primary oral and maxillofacial liposarcoma: a clinicopathological and immunohistochemical study of eleven cases

INTRODUCTION

The present study was aimed to characterize the clinicopathological, immunohistochemical features and treatment outcomes of primary oral and maxillofacial liposarcomas by presenting the experience over a 16-year period at a tertiary referral Chinese institution for head neck cancer.

MATERIAL AND METHODS

This retrospective clinical study included 11 cases of pathologically confirmed primary liposarcomas treated from January 1993 to September 2009. Detailed information regarding primary site, clinical manifestations, histopathological and immunohistochemical analysis, treatments and prognosis was collected and reported.

RESULTS

Eight female and 3 male patients aged from 8 to 76 years old. These lesions occurred in buccal (3), parotid (2), temporal (2), tongue (2), palate (1) and oropharyngeal (1) region. They were histopathologically categorized into 4 subtypes based on WHO classification scheme: atypical lipomatous tumor/well-differentiated (4), myxoid (4), mixed-type (2) and pleomorphic (1) liposarcomas. Immunohistochemical staining indicated mostly positive for Vimentin and S-100 but negative for other markers. Most patients presented as slow-growing painless masses and underwent surgery alone or combined with postoperative radiotherapy. Two patients were misdiagnosed and inappropriate treated and developed local relapse before referred to our institute. No distant metastasis and one disease-related death were recorded during the follow-up (ranging: 1-11 years, mean: 4.5 years).

CONCLUSIONS

Oral and maxillofacial liposarcoma is exceedingly rare and has atypical clinical manifestations but characteristic histopathology. Complete excision with negative margins followed by long-term follow-up is recommended as the treatment of choice for these uncommon entities.

[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.

Fine needle aspiration of pleomorphic lipoma of the neck: report of two cases

Pleomorphic lipoma is a rare lipocytic neoplasm that most commonly occurs in the head and neck region in middle-aged to elderly men. Clinically, it presents as a slow-growing, well-circumscribed subcutaneous mass. Histopathologically and cytogenetically, it has some features overlapping with other benign and malignant tumors, such as benign spindle cell lipoma, atypical lipomatous tumor, liposarcoma, and malignant fibrous histiocytoma. However, cure rates are high when pleomorphic lipoma is treated with complete surgical excision with clear margins. Therefore, an accurate preoperative diagnosis is very important for proper treatment. Due to the rarity of this tumor, few cases diagnosed by cytology have been reported in the English literature. Here, we report two cases of pleomorphic lipoma, the diagnoses of which were suggested on fine needle aspiration biopsies and subsequently confirmed by surgical excisions.

[Cytologic diagnosis of soft tissue tumors]

Soft tissue swellings represent common clinical signs of a variety of neoplastic and non-neoplastic lesions. Sarcomas are rarely the cause. Fine needle biopsy as a minimally invasive, economic and accurate method is well suited for the diagnostics of recurrent and metastatic diseases. Cytologic diagnosis of primary soft tissue tumors is also feasible but 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 also important parameters. Differentiation of the cells and the properties of the extracellular matrix offer initial indications for the differential diagnosis and are the starting point for immunohistochemical and molecular analyses (FISH, RT-PCR). These analyses can be performed on cytological smears, on paraffin-embedded cell blocks on snap frozen material.

A (9;11)(q34;q13) translocation in a hibernoma

The diagnosis of hibernoma has historically been made by histopathologic examination and finding of characteristic brown fat cells with granular multivacuolated cytoplasm. The diagnosis of hibernoma may be complicated, however, because seemingly diagnostic cells could be mistakenly identified as lipoblasts, leading to the erroneous diagnosis of well-differentiated liposarcoma. Cytogenetic alterations in lipomatous tumors are well established and could be used for diagnostic purposes. Previous cytogenetic abnormalities reported in hibernomas have included alteration of 11q13 region. Here, we present a case of a hibernoma with a novel cytogenetic alteration involving a reciprocal translocation between 9q and 11q that was useful in establishing the final diagnosis.

Cytopathology-histopathology of the mediastinum

An appraisal of the cytopathology and corresponding histopathology of epithelial, germ cell, and lymphoid lesions of the mediastinum was previously reported in the Journal. This report aims to complete that topic with a discussion focusing on the correlative cyto-histopathology of the major mesenchymal, neural, and neuroendocrine neoplasms from this anatomic site. As previously stated, the mediastinum remains an uncommon site for fine needle aspiration (FNA) biopsy when compared with other anatomic sites. Yet, the recent use of endoscopic ultrasound-guided FNA for sampling mediastinal masses may increase this use. The purpose of this review is to focus on the shared and dissimilar morphologic features of this subset of neoplasms to improve diagnostic correlation between the two.