Distinct cytologic features of spindle cell lipoma. A cytologic-histologic study with clinical, radiologic, electron microscopic, and cytogenetic correlations

Spindle cell lipoma of the tongue: First case report from the Gulf region and review of the literature

Spindle cell lipoma is a histological variant of oral lipomas. In this report, we present the first case from the Gulf region with the most comprehensive literature review. Clinicians should consider rare tumors in the differential diagnoses of oral masses.

Unusual presentation and management of spindle cell lipoma: A case report

Spindle cell lipoma is a benign tumor composed of mature adipocytes and uniform spindle cells, it does not exceed usually more than 2.5 cm and can be treated surgically and does not require wide surgical margins. It must be differentiated from liposarcoma and other malignant tumours and can be differentiated based on imaging and histological features. We report a case of 67-year-old male who developed a posterior thoracic mass more than 10 years ago, that grew recently, whose imaging features was suggestive of liposarcoma, and was treated as such.

Atypical spindle cell/pleomorphic lipomatous tumour (ASPLT): A report of three FNA cases and comparison with spindle cell/pleomorphic lipoma cytopathology

INTRODUCTION

Atypical spindle cell/pleomorphic lipomatous tumour (ASPLT) is an infrequently appreciated benign lipomatous neoplasm newly accepted into the most recent WHO classification of soft tissue tumours.

MATERIALS AND METHODS

Our cytopathology files were searched for examples of ASPLT and spindle cell/pleomorphic lipoma (SCPL) having histopathological verification. Conventional fine needle aspiration (FNA) biopsy smears were performed using standard techniques.

RESULTS

Eleven patients including three cases of ASPLT and eight of SCPL (M:F = 4.5:1; age range: 39-97 years, mean age = 60 years) met the inclusion criteria. FNA biopsy sites included extremity (5, 45%), trunk (3, 27%), and head/neck (3, 27%). All aspirates were from primary neoplasms. FNA diagnoses of ASPLT cases were spindle cell lipomatous neoplasm, fibrotic low-grade SC neoplasm, and myxoid lipomatous neoplasm. Eight SCPL cases were diagnosed as spindle cell neoplasm (3), spindle cell lipoma (SCL) (1), pleomorphic lipoma (1), suspicious for SCL (1), benign adipose tissue (1), and benign spindle cells and connective tissue (1). Ancillary testing in two ASPLT cases showed positive CD34 and negative MDM2 immunostain in one, and negative FISH results for MDM2 and DDIT3 in another.

CONCLUSION

ASPLT is a novel lipomatous neoplasm simulating primarily SCPL and atypical lipoma/well-differentiated liposarcoma. Diligent cytomorphological observation, clinical information, and ancillary testing may allow for its specific recognition using FNA biopsy.

Comprehensive Review of Reported Nonclassical Spindle Cell Lipoma Presentations and a Unique Case Report

Introduction:

Spindle cell lipoma (SCL) is a rare subset of benign lipomatous neoplasms, making up approximately 1.5% of all adipocytic neoplasms. Since SCLs were first described in 1975, numerous nonclassical cases have been reported in the literature, with variation in location, cytologic composition, patient demographic, and progression. Although some previous reports review related cases of specific rare presentations or institution-based summaries, no comprehensive summary of published nonclassical SCL case reports has been done.

Methods:

PubMed was queried for nonclassical presentations of SCL from 1978 to 2018. The nonclassical characteristics were analyzed and described. Those with multiple nonclassical features were studied for common characteristics. The Fisher exact test was used, and a P value of 0.05 was determined to be statistically significant.

Results:

We present the first case of a patient with six nonclassical findings: a fast-growing, infiltrating into skeletal muscle, located in two positions on the chin of an 18-year-old African American woman. In this review of the existing nonclassical SCL, we evaluate 125 cases for demographics, location, size, erosion/infiltration, multiple lesions in one individual, and the number of nonclassical findings in one individual. Women and younger than 40-year-old patients significantly present with more than one nonclassical finding.

Conclusions:

Thorough characterization of the rare nonclassical cases of this benign condition could guide diagnostic decision-making and identify trends in disease presentation over time as well as alert the clinician to the increased risk of rapid regrowth or invasion in an individual with nonclassical findings especially young age and female gender.

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.

Spindle cell lipoma mimicking pleomorphic adenoma: A diagnostic challenge on cytology

Spindle cell lipoma (SCL) is a benign neoplasm of mature adipose tissue mostly located in the neck, back, and shoulder region. It is composed of a variable admixture of adipocytes, benign spindle cells, and collagen fibres. While the histopathologic features of SCL are quite characteristic and well described, a cytologic diagnosis of SCL might be challenging. We present a case of a 36-year-old female with a swelling in the left preauricular region since last 6 mo. On fine needle aspiration, a diagnosis of lipomatous pleomorphic adenoma (PA) was rendered because of the presence of benign spindle-shaped cells, adipocytes, and abundant myxoid material. However, on histopathologic examination, the diagnosis was SCL which was confirmed by immunohistochemistry. Preauricular region is a rare site of occurrence of SCL. An acquaintance with its varied cytomorphologic features and a knowledge of its unusual sites of occurrence is essential to prevent its misdiagnosis as other myxoid benign and malignant spindle cell lesions.

Cytogenetics of Spindle Cell/Pleomorphic Lipomas: Karyotyping and FISH Analysis of 31 Tumors

BACKGROUND

Spindle cell/pleomorphic lipomas are benign tumors. Here, we present our cytogenetic data on 31 such tumors.

MATERIALS AND METHODS

G-banding chromosome analysis and (in selected cases) fluorescence in situ hybridization (FISH) using probes for FOXO1, RB1, and HMGA2 were performed.

RESULTS

Rearrangements of chromosome 13 were found in 58% of tumors. Chromosomes 6, 1, 12, and 11 were also involved in 42%, 26%, 26%, and 23% of tumors, respectively. FISH analysis showed heterozygous deletion of RB1 in seven samples with chromosome 13 aberrations. In four of them, FOXO1 was also deleted. In two tumors with 12q15 rearrangements, FISH confirmed that HMGA2 was targeted.

CONCLUSION

Structural rearrangements of 13q or losses of an entire chromosome 13 are the most common cytogenetic aberrations in spindle cell/pleomorphic lipomas. However, cytogenetic variation exists similarly to what is found in other lipomas, suggesting that various pathways may be responsible for tumorigenesis.

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.

Cytohistological Features of Spindle Cell Lipoma- A Case Report with Differential Diagnosis

Spindle Cell Lipoma (SCL) is an uncommon benign tumour of adipose tissue that is usually superficially located in the neck, back and shoulder region. Although it has characteristic histological features it can pose a diagnostic dilemma on cytology. It presents with a mixture of spindle cells, adipocytes, collagen fibres and a myxoid matrix in varying proportions sometimes with mild pleomorphism. Hence, it can be mistaken for other spindle cell, adipose and myxoid tumours which can be benign or malignant. We present a case of SCL of the back in a 47-year-old male, who presented with a slow growing lesion. Fine Needle Aspiration Cytology (FNAC) showed the characteristic cytological features described above and a diagnosis could be given after clinical correlation. We report this case as the cytology of this uncommon tumour has been described in relatively few cases and a correct pre-operative diagnosis will aid in proper management of this tumour.

Spindle Cell Lipoma of the Neck: Review of the Literature and Case Report

Spindle cell lipomas (SCL) are benign, slow growing tumors arising most frequently in the subcutaneous tissue of the upper back, posterior neck, and shoulders in males aged 40-70 years. Local excision is generally curative. Classification of lipomatous tumors has progressed recently, and tumors of similar morphology and unusual presentation are increasingly reported, thereby making correct diagnosis even more vital. SCL require pathologic differentiation from liposarcoma, other spindle cell neoplasms, and myxoid lesions for treatment purposes. Cytology, histology, and cytogenetics, in conjunction with clinical presentation, are paramount in arriving at the correct diagnosis of spindle cell lipoma. We present a case report with characteristics typical of an SCL along with a literature review to further elucidate the diagnosis and surgical treatment of this soft tissue tumor.

Spindle cell lipoma with predominant nerve sheath tumor-like areas: A potential diagnostic pitfall on aspiration cytology

Spindle cell lipoma (SCL) is an uncommon variant of lipoma that usually is present in subcutaneous fat of adult men. This tumor has a low rate of local recurrence and no risk of malignant behavior. Although histological features of SCL are well documented, cytological descriptions have been few. We present the case of a 41-year man with a right arm swelling, which on fine-needle aspiration cytology showed adipose tissue fragments, spindle cell areas mimicking benign nerve sheath tumor, and bundles of ropy collagen in a myxoid background, suggesting a diagnosis of SCL. SCL with predominant spindle cell component may mimic benign nerve sheath tumor on aspiration cytology. Subtle cytological features like presence of adipose tissue, ropy collagen, and mast cells help in accurate diagnosis.

Spindle cell lipoma

Spindle cell lipomas (SCLs) are a group of benign lipogenic tumours, typically arising in the posterior neck, upper back and shoulder of elderly male patients. Approximately 80% of these tumours arise in characteristic location, but 20% arise in unusual locations, thereby making these cases more difficult to diagnose. We present a case of SCL occurring in the right periorbital region of a 14-year-old boy. The MRI was suggestive of possible malignancy. Diagnosis of neurofibroma was made on incisional biopsy. However, the histopathological and immunohistochemical analyses of the excised lesion confirmed the diagnosis of SCL.

Spindle cell lipoma masquerading as lipomatous pleomorphic adenoma: A diagnostic dilemma on fine needle aspiration cytology

Spindle cell lipoma is a relatively uncommon benign adipocytic tumor that usually presents in subcutaneous fat of adult men. These are a rare form of lipoma, accounting for 1.5% of all lipomatous tumors, with a low rate of local recurrence and no risk of malignant behavior/dedifferentiation. Although few studies addressing the histological findings of spindle cell lipoma have been described, only a few descriptions of fine needle aspiration cytology (FNAC) findings have been documented in literature. We present a case of a 55-year-old male with a nodular swelling over left cheek (in the parotid region), which due to its location as well as prominent myxoid background prompted us to include the lipomatous salivary gland lesions in differential diagnosis. Our objective is to document and delineate the characteristic cytological features of spindle cell lipoma, which may permit a confident diagnosis on FNAC smears.

Low-grade fibromyxoid sarcoma is difficult to diagnose by fine needle aspiration cytology: a cytomorphological study of eight cases

BACKGROUND

Low-grade fibromyxoid sarcoma (LGFMS) is an uncommon neoplasm with bland morphology and an indolent clinical course, although metastases may develop in approximately 5-10% of the cases. The diagnosis of LGFMS can be difficult to render from fine needle aspiration cytology (FNAC) alone because of morphological overlap with other spindle cell and myxoid lesions.

OBJECTIVE

To determine cytological criteria for LGFMS by reviewing FNAC aspirates in eight cases and to compare the findings with those in subsequent histological sections.

METHODS

FNAC slides were reviewed from eight patients with subsequently excised tumours diagnosed as LGFMS. Of these patients, six also had core needle biopsies (CNB). Cytogenetic and/or molecular analysis was carried on all tumours.

RESULTS

The patients were six men and two women ranging in age from 26 to 78 years. Tumours arose in the deep soft tissues of the thigh (n = 5), shoulder girdle (n = 1) or upper arm (n = 1) and one in the subcutaneous tissue of the abdominal wall. Cytological features included clusters of bland spindle and round/polygonal cells embedded in a collagenous and myxoid matrix along with dissociated, uniform or slightly/moderately pleomorphic spindle cells, bare nuclei and fragments of collagen and myxoid tissue in varying proportions. Unequivocal sarcoma was diagnosed in two aspirates, but mitoses were absent in all cases. In three cases, the diagnosis was inconclusive with regard to benignity or malignancy, while three were erroneously diagnosed as benign spindle cell lesions. Although the diagnosis was suggested on three of six CNB, these presented similar diagnostic problems.

CONCLUSIONS

There were no cytomorphological findings in FNAC to allow for a clear cut separation of LGFMS from other spindle cell or myxoid lesions, but high-grade sarcoma could be excluded. Surgical (incisional or excisional) biopsy or, alternatively, examination of RT-PCR for the FUS/CREB3L or FUS/CREB3L1 fusion transcripts may be necessary to obtain a correct diagnosis.

Fine-needle aspiration of neurilemoma (schwannoma). A clinicocytopathologic study of 116 patients

The preoperative fine-needle aspiration cytology (FNAC) diagnoses in 116 surgically excised neurilemomas were reviewed and compared with the corresponding histopathologic diagnoses made on surgical specimens and with clinical data. In addition, the utility of adjunctive techniques was analyzed and other spindle-cell lesions in the differential diagnoses were discussed. An unequivocal, benign diagnosis was rendered by FNAC in 80 cases, 67 of which were correctly labelled as neurilemoma in a review of the original cytology reports. There were 6 false-positive malignant diagnoses while 23 smears were considered insufficient and 7 inconclusive as to whether benign or malignant. On reevaluation, the diagnostic smears in most cases contained spindle cells with wavy nuclei embedded in a fibrillar, occasionally collagenous, and/or myxoid matrix and Antoni A/Antoni B tissue fragments. A moderate to abundant admixture of round to oval cells was also frequent. Nuclear palisading was seen in 41 smears with distinctive Verocay bodies in 10. Markedly pleomorphic nuclei were seen in smears from 8 ancient and 6 conventional neurilemomas, and slight to moderate nuclear pleomorphism was observed in 38 additional cases. Thus most neurilemomas have distinct cytomorphologic features that allow correct diagnosis. The major problem in FNAC of neurilemoma is to obtain sufficient material. Furthermore aspirates showing predominantly Antoni A features, nuclear pleomorphism, and/or myxoid changes can easily be confused with other types of benign or malignant soft-tissue tumors.

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

We have reviewed cytopathology and the corresponding histopathology material of 86 liposarcomas (55 patients) seen at Institut Curie. The liposarcomas (LS) were well differentiated in 14 cases (9 pure, 2 dedifferentiated, 3 sclerosing), 64 myxoid, and 8 pleomorphic. Twenty-four tumors were primary, 34 recurrent, and 28 secondary. Smears in LS were composed in different proportions of round, spindle cells, lipoblasts, and myxoid and vascular arborizing structures. Pure well-differentiated LS were frequently composed of lipoblasts, and round or spindle cells were occasionally seen. Dedifferentiated and sclerosing liposarcomas were composed of spindle or round cells, but lipoblasts were also occasionally present. Myxoid or vascular arborizing structures were absent. Myxoid LS (including round and spindle cell LS) frequently showed a myxoid background and less frequently vascular arborizing structures. Tumor cells were round or spindle. Lipoblasts were also seen. Pleomorphic LS were composed of an admixture of all cellular and stromal elements. Well-differentiated LS should be distinguished from hibernoma and spindle cell lipoma, and myxoid LS from myxoma, myxoid chondrosarcoma, chordoma, myxoid leiomyosarcoma, and myxoid malignant fibrous histiocytoma. The demonstration of the specific translocation t(12;16)(q13;p11) of myxoid LS is very helpful to establish the diagnosis. Pleomorphic LS should be differentiated from other high-grade sarcomas, whenever possible.

Chromosomal abnormalities and DNA image cytometry of haematological neoplasms in fine needle aspirates of lymph nodes

The current diagnostics of haematological neoplasms along with morphological analysis, immunophenotyping and molecular analysis inevitably includes cytogenetic analysis. In this work the possibility of cytomorphological subclassification of haematological neoplasms from lymph node fine needle aspirates was examined without depending upon the referential histological diagnosis and cytogenetic analysis. In addition, the feasibility of cytogenetic analysis of the material obtained by lymph node fine needle aspiration (FNA) was examined. By analysing the findings of cytogenetic analysis and DNA image cytometry, it was decided to examine the possibility of comparing the findings and supplementing diagnostic possibilities of these methods. In 15 cases cytological diagnoses and cytogenetic analysis of haematological neoplasms were performed on the material obtained by lymph node FNA. In 12 of 15 cases histological diagnosis was made separately. A good cytohistological correlation was available in 9 of 12 cases (75%). Cytomorphological diagnoses in 10 of 15 cases (76%) were confirmed by the finding of a specific chromosomal translocation. In two cases cytological diagnosis did not correlate with the histological diagnosis and was confirmed only with specific chromosomal translocations. The lymphocytes obtained by lymph node FNA were adequate material for cytogenetic analysis - in 15 of 18 (83%) cases mitoses in cell cultures were obtained. In 13 of 15 (87%) cases clonal chromosomal abnormalities were detected, whereas in 2 of 15 (13%) cases a normal karyotype was found. DNA image cytometry was performed on nine samples, whereas in six samples the material was not sufficient. Although a small number of samples was analysed in the cases with identical cytomorphological diagnoses, the analysed histograms regarding the DNA index values showed heterogeneity. In conclusion, a cell culture sampled by FNA of lymph nodes is an adequate method for the chromosomal analysis. The specific cytogenetic abnormality associated with cytological diagnosis provides an opportunity to make a definitive diagnosis and provides a powerful approach when reference diagnosis on biopsy material cannot be obtained.

Elastofibroma dorsi has distinct cytomorphologic features, making diagnostic surgical biopsy unnecessary: Cytomorphologic study with clinical, radiologic, and electron microscopic correlations

Elastofibroma dorsi (EFD) is a relatively rare soft tissue mass, probably of reactive nature. The lesion is typically located near the inferior margin of the scapula or between the inferior part of scapula and the chest wall in elderly women. Although location of the tumor together with the age/sex of the patients and radiologic findings is often suggestive of the diagnosis, tissue examination has been considered necessary to confirm the diagnosis. Although the histologic features of EFD are well known, there are only four single case reports of the cytologic findings in the English language literature. We describe the cytologic features of EFD in five patients with correlations to clinical, radiologic, histologic, and electron microscopic findings. The current study suggests that the fine-needle aspiration (FNA) features are highly diagnostic, permitting a firm diagnosis of EFD in a typical clinical setting and eliminating the need for preoperative histologic examination.

Fine-needle aspiration smears from lipomatous hemangiopericytoma need not be confused with myxoid liposarcoma

Lipomatous hemangiopericytoma (LHPC) is a rare benign soft tissue tumor that may mimic soft tissue sarcoma clinically. Despite the fact that LHPC shares most of the histologic features with solitary fibrous tumor, it may be occasionally misdiagnosed as myxoid liposarcoma or some other type of spindle-cell sarcoma. While some studies have addressed the histological features and origin of LHPC, no reports of cytological findings have been published. The author describes the cytological features of LHPC in two patients with correlations to histological and clinical findings. One of aspirates was misdiagnosed as being myxoid liposarcoma, while the other one was correctly diagnosed by a combination of FNAB and core needle biopsy (CNB). Cytological evaluation of LHPC can be problematic due to its rarity and to its similarity with other spindle-cell or fatty tumors. Correct diagnosis requires an awareness of cytologic features of this rare tumor and the use of ancillary studies.

Acral myxoinflammatory fibroblastic sarcoma in FNAB samples: can we distinguish it from other myxoid lesions?

We analysed cytomorphological characteristics of three fine needle aspiration biopsy (FNAB) samples of acral myxoinflammatory fibroblastic sarcoma (AMIFS) as well as the features of a number of other benign and malignant myxoid lesions. The analysis showed that FNAB samples from two cases of AMIFS had similar cytomorphology, containing all the characteristic features described in surgical biopsies: myxoid material, spindle cells with bipolar cytoplasmic extensions, epithelioid cells with globules of extra-cellular material, ganglion-like and lipoblast-like giant cells. Only the inflammatory component was scarce. The third sample did not contain features typical of AMIFS. Samples from other myxoid tumours resembled AMIFS to some extent, however, none of them contained all three tumour components characteristic of AMIFS. Cytomorphology of AMIFS may be characteristic enough to enable a definitive diagnosis from FNAB, provided all the distinctive features are sampled.

Cytologic features of primary, recurrent, and metastatic dermatofibrosarcoma protuberans

BACKGROUND

Dermatofibrosarcoma protuberans (DFSP) is a low-grade spindle cell neoplasm involving both dermis and subcutis. Its diagnosis may be difficult to render from cytologic smears, as it shares some features with other spindle cell lesions occurring in the skin and soft tissue.

METHODS

Fourteen aspiration smears from 12 patients with primary, recurrent, or metastatic DFSP, examined by fine-needle aspiration biopsy (FNAB), were reviewed and compared with corresponding surgical specimens (13 aspirates) and clinical data (one aspirate). The cytologic features of DFSP were evaluated. Other spindle cell lesions in the differential diagnoses were discussed.

RESULTS

Unequivocal spindle cell sarcoma diagnoses were rendered in nine aspirates, six of which were labeled correctly as DFSP in the original reports. In three aspirates, the preoperative diagnoses were inconclusive with regard to whether the tumors were benign or malignant. Two aspirates were diagnosed erroneously as benign spindle cell lesions. Cytologic features included tight clusters of bland spindle cells embedded in a collagenous/fibrillar and, often, metachromatic matrix along with dissociated, uniform, or slightly atypical spindle cells or bare nuclei. Tissue fragments showing a storiform pattern and entrapped fat tissue, reported in previous series, were less characteristic, presenting in nine and seven aspirates, respectively.

CONCLUSIONS

Correct subtyping of DFSP in fine-needle aspiration smears can be difficult, due to its morphologic overlapping with other spindle cell lesions. A combination of cytology with ancillary studies and appropriate clinical information is crucial to establishing a correct diagnosis.