Pleomorphic Lipoma Research Articles

Spindle Cell Lipoma and Pleomorphic Lipoma in the Head and Neck: A Comprehensive Study of Six Cases With Review of Literature.

Spindle cell lipomas (SL) and pleomorphic lipomas (PL) are rare variants of lipomas, occurring predominantly in the head and neck region. Laryngeal SL/PL is very uncommon and causes obstructive symptoms needing immediate intervention. These tumors are often challenging in radiology due to the admixture of elements and the presence of adipose tissue may help in diagnosis. From a surgeon's perspective, understanding the nuances of SL/PL is paramount. Histology is the gold standard for diagnosis; however, it often causes diagnostic challenges in biopsy. Method: A retrospective review of the clinical and pathologic features of archival cases of SL/PL was performed. A total of six cases of head and neck region SL/PL were identified. The age of patients ranged from 21 to 58 years and the male-to-female ratio was 5:1. The tumors were distributed in the nape of the neck (n=3), laryngeal region (n=2), and orbit (n=1). Histology in all the cases showed a low-grade neoplasm composed of a variable amount of spindle cells and adipose tissue. The stroma was myxoid in most cases. CD34 was diffusely positive in all the cases. SLs are a rare and uncommon variant of lipoma with a predilection in the head and neck region. They are low-grade neoplasms with a propensity to recur after years. Having knowledge of this tumor can improve surgical outcomes and better patient care.

Benign Lipomatous Soft Tissue Tumors in Nigerians: An Analysis of the Clinical and Morphological Features of a Common but Important Entity.

Introduction Benign lipomatous tumors are soft tissue tumors that exhibit a predominant adipocytic phenotype. Lipomas are the archetype and are the most common benign soft tissue tumors in adults but relatively uncommon in children. Their sex incidence is equivocal. They sometimes occur in combination with other mesenchymal elements, giving rise to variants including fibrolipoma, angiolipoma, myolipoma, spindle cell lipoma, chondroid lipoma, osteolipoma, and chondrolipoma. Their clinical significance is mainly due to the cosmetic disfigurement of patients and the differential diagnosis of malignant soft tissue tumors. Occasionally, due to their large size or presence near vital organs, they may cause life-threatening and/or excruciating pressure symptoms. This study was purposed to address the dearth of local studies on the clinical and morphological characteristics of benign lipomatous tumors in Nigerians, to compare these with those of other populations, and to establish baseline data. Materials and methods This was a retrospective study of all benign lipomatous tumors seen in the anatomic pathology and forensic medicine department of Asokoro District Hospital, Abuja, Federal Capital Territory, Nigeria, over an eight-year period. Surgical pathology reports were retrieved for patients' biodata and clinical information. The appropriate slides were retrieved, and reviewed, and new sections were cut where necessary. The tumors were classified according to the 2020 World Health Organization (WHO) guidelines and categorized based on size as small, medium, or giant. The data obtained were analyzed, and the results were presented as tables, bar charts, ratios, and percentages. Results Four hundred and eighteen cases met the inclusion criteria. Of these, 58.4% (244/418), occurred in females, while 41.6% (174/418) occurred in males. The age range was six to 91 years, while the median age was 42 years. The least number of cases, 0.5% (2/418), were seen in patients aged less than 10 years, while the majority, 35.4% (148/418), occurred in the fifth decade, followed by 27.8% (116/418) in the fourth. Size-wise, the majority of tumors, 60% (253/418), were medium, followed by small, 22.8% (95/418). Giant-sized tumors significantly accounted for 16.7% (70/418) of the cases. The diagnostic spectrum comprised conventional lipoma and variants such as fibrolipoma, spindle cell lipoma, pleomorphic lipoma, angiolipoma, chondrolipoma, intramuscular lipoma, and osteolipoma. Lipoma and fibrolipoma dominated with 87.1% (364/418) and 10.0% (42/418), respectively, while the rest accounted for <3%. The majority, 31.8% (133/418), occurred in the back/shoulder region, followed by the lower limb with 18.2% (76/418). Only two cases occurred in the abdominal/pelvic region. More tumors occurred in females in all the regions except the head and neck, which had a male-to-female ratio of 1.5:1. Multiple site tumors were more common in males in a ratio of 2.5:1. Most, 41.1% (39/95), of the small-sized tumors, occurred in the head/neck region, largely involving the face, 48.7% (19/39). Conclusion Our study showed many similarities in the clinical and morphological features of benign lipomatous tumors between Nigerians and other regions of the world. A notable finding, however, was the significantly higher proportion of giant benign lipomatous tumors when compared tostudies from other regions, a finding that warrants further studies.

Pleomorphic Lipoma of the Parotid Gland: A Potential Cytological Pitfall.

Pleomorphic lipoma is an uncommon benign adipocytic tumor that arises from the subcutis. It has no risk of recurrence, metastasis or malignant transformation. The cytological findings of pleomorphic lipoma are often overdiagnosed as suspicious of malignancy owing to the pleomorphic morphology of the floret giant cells. We present a rare case of pleomorphic lipoma of the parotid gland which was misdiagnosed as a malignant tumor on fine needle aspiration cytology. Histopathological examination and positive expression for CD34 helped to arrive at the final diagnosis. Awareness about this rare entity will prevent overdiagnosis as a malignant tumor and unnecessary radical resections for this benign tumor.

Case Report: an unusual orbital tumor

Introduction: Orbital lipoma is an extremely rare tumor, representing less than 1% of all orbital tumors. We review the literature and describe the presentation, the differential diagnosis and the management of this tumor. Case report: We report the case of a 63-year-old patient who was referred for a diplopia with recent hemi-cranial headache. Physical examination showed no exophthalmos nor decrease in visual acuity. The patient complained of diplopia on elevation and oculomotricity examination showed limited elevation of the right eye. The Hess Lancaster test was in favor of a limited course of the right inferior rectus muscle. Magnetic resonance imaging revealed a fusiform tissue process in the right inferior rectus muscle with a fatty signal. A complete excision of the tumor was performed by a trasncunjonctival approach. Cytopathological examination was consistent with a pleomorphic lipoma. The postoperative period was uneventful. The definitive histopathologic diagnosis was a lipoma. The postoperative Magnetic resonance imaging showed the complete disappearance of the lesion. With 3 years of follow up, there is no sign of recurrence or ocular motility trouble. Conclusion: Lipomas are rare tumors in the orbit. The clinic is variable depending on the size and the site. The clinical diagnosis is difficult to make. Only histology allows the final diagnosis.

Spindle Cell Lipoma and Pleomorphic Lipoma: An Update and Review.

Spindle cell lipoma (SCL) is a benign adipocytic tumor that primarily occurs in the subcutis of the posterior neck, upper back, and shoulder, particularly of middle-aged males. SCL and pleomorphic lipoma (PL) represent a morphological spectrum of one disease process. The lesion typically presents as a relatively small (<5 cm), mobile, slow-growing, painless mass. Magnetic resonance imaging reveals the lesion to be a well-defined subcutaneous mass with a mixture of adipose and non-adipose components. Intense enhancement of the non-adipose component is seen after contrast administration. Histologically, SCL is composed of variable distributions of mature adipocytes, bland spindle cells and ropey collagen bundles and PL also contains pleomorphic and multinucleated floret-like giant cells. By immunohistochemistry, the spindle and pleomorphic/floret-like giant cells of SCL/PL are diffusely positive for CD34 and show loss of nuclear RB transcriptional corepressor 1 (RB1) expression. Recent cytogenetic and molecular genetic studies have shown heterozygous deletions of 13q14, including the RB1 gene. SCL/PL can be successfully treated with simple excision, with a very low recurrence rate. Knowledge of these peculiar tumors is important because it can mimic a variety of benign and malignant soft-tissue tumors. This review provides an updated overview of the clinical, radiological, histopathological, cytogenetic, and molecular genetic features of SCL/PL.

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

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. 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. 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. 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.

Histopathologic and genetic findings in atypical spindle cell/pleomorphic lipomatous tumors and atypical pleomorphic fibromas.

Spindle cell lipomas, pleomorphic lipomas (SCL/PLs), and pleomorphic fibromas (PF) are tumors with loss of retinoblastoma (RB). The latest World Health Organization classification includes a category of atypical spindle cell/pleomorphic lipomatous tumors (ASPLT), which encompasses tumors in this spectrum that show atypical histopathologic features. We have observed PFs that show similar atypical features. Cases of SCL/PL and PF with atypical features were collected from tissue archives between 2010 and 2019. Genetic alterations were investigated using array comparative genomic hybridization (aCGH). Of 15 cases found, most tumors were dermal based with fibrocytic or fibroadipocytic appearance and occasional lipoblasts. All cases had a high proliferation index with atypical mitotic figures in 71% of cases. Chromosome 13q loss was present in all cases with CGH data. Additional recurrent chromosomal losses included 17p, 16q, 17q, 20p, 4, and 10. No recurrence was found in limited follow-up. ASPLTs are characterized by loss of RB, prominent nuclear pleomorphism, mitotic activity including atypical mitotic figures, and genomic instability with multiple chromosomal aberrations. A similar group of tumors with these histopathologic features lacks lipomatous differentiation, and we propose the diagnosis of atypical PF as a fibromatous variant of ASPLT. Limited clinical follow-up appears benign.

Oral Fibrolipoma Arising from Maxillary Alveolus: A Rare Case Entity

Lipoma is a non malignant tumour of adipocytes. Lipomas are most commonly seen during 4th to 6th decades of life. About 20% lipomas are seen in head and neck region of which only 1% to 4% have been reported in oral cavity. Most common site of occurance in oral cavity is buccal mucosa and tongue (50%). Various histological variants of lipoma have been identified, which include fibrolipoma, angiolipoma, infiltrating (intramuscular) lipoma, pleomorphic lipoma, osteolipoma, sialolipoma, chondrolipoma, myxolipoma and spindle cell lipoma. Fibrolipoma is a rare histological variant and occurrence on alveolus is even rare. Thus, reporting a case of Fibrolipoma of size 2×2 cm arising from maxillary alveolus in a 42-year-old female patient with a long standing history of 4 years

Oral Fibrolipoma: A Rare Histological Subtype

Lipomas are soft tissue tumors who originate from adipose tissue. Histologically, subtypes ends are defined. These are fibrolipoma, angiolipoma, myxoid lipomas, spindle cell lipoma, pleomorphic lipoma and intramuscular lipoma. When a large proportion of connective tissue is present, the term fibrolipoma is used. Fibrolipoma subtype of the oral cavity is rare. The tumor has been reported to be more frequent in the buccal mucosa. This case report describes the treatment of an asymptomatic fibrolipoma lesion in the right buccal mucosa by local excision. Since asymptomatic lesions usually can only be detected in intraoral examination, physicians should be careful during clinical examinations and have information about rare histological subtype.

Pleomorphic lipoma: A rare entity

Pleomorphic lipoma is a rare neoplasm that is considered as a variant of spindle cell lipoma. It predominantly occurs in the dermis or subcutis of the posterior neck, upper back, and shoulders. Pleomorphic lipoma may clinically present as a slow-growing and well-circumscribed subcutaneous mass. Though it is a benign tumour it may contain atypical cells for which it may mimick sarcoma or other malignant soft tissue tumours. So histopathological diagnosis is vital for preventing unnecessary surgery. Here we report a case of a pleomorphic lipoma on upper back in a 55yr old patient.

Telocytes/CD34+ Stromal Cells in Pathologically Affected White Adipose Tissue

We studied telocytes/CD34+ stromal cells (TCs/CD34+SCs) in pathologically affected white adipose tissue after briefly examining them in normal fat. To this aim, we reviewed pathological processes, including original contributions, in which TCs/CD34+SCs are conserved, increased, and lost, or acquire a specific arrangement. The pathologic processes in which TCs/CD34+SCs are studied in adipose tissue include inflammation and repair through granulation tissue, iatrogenic insulin-amyloid type amyloidosis, non-adipose tissue components (nerve fascicles and fibres in neuromas and hyperplastic neurogenic processes) and tumours (signet ring carcinoma with Krukenberg tumour and colon carcinoma) growing in adipose tissue, adipose tissue tumours (spindle cell lipoma, dendritic fibromyxolipoma, pleomorphic lipoma, infiltrating angiolipoma of skeletal muscle and elastofibrolipoma), lipomatous hypertrophy of the interatrial septum, nevus lipomatosus cutaneous superficialis of Hoffman–Zurhelle and irradiated adipose tissue of the perirectal and thymic regions. Two highly interesting issues emerged: (1) whether the loss of CD34 expression in TCs/CD34+SCs is by changes in marker expression or the disappearance of these cells (the findings suggest the first possibility) and (2) whether in some invasive and metastatic malignant tumours, TCs/CD34+SCs that completely surround neoplastic cells act as nurse and/or isolating cells. Further studies are required on adipose tissue TCs/CD34+SCs, mainly in lipomatosis and obesity.

An Unusual Presentation of Pleomorphic Lipoma

Abstract Introduction/Objective Pleomorphic lipomas are benign tumors that typically occur in the shoulder, posterior neck, and back. Here, we present a case of a pleomorphic lipoma arising in an unusual location. Methods A 63-year-old male presented with a 1.3 x 1.3 x 0.9 cm enhancing slightly heterogeneous mass in the subcutaneous tissue superficial to the right parotid tail. The mass was biopsied and then excised. Results Histopathologic examination of the biopsy and resection specimens revealed an adipocytic neoplasm composed of mature adipose tissue with admixed spindle cells within a myxoid stroma. Lipoblasts, cellular atypia or increased mitotic figures were absent. Numerous floret-like cells were identified. These floret cells are characteristic of pleomorphic lipoma. The tumor cells were diffusely positive for CD34 and negative for desmin, smooth muscle actin, MyoD1, keratin, SOX10, and Melan-A by immunohistochemistry, consistent with pleomorphic lipoma. Conclusion Pleomorphic lipomas arising from the periparotid adipose tissue are rare. They tend to have a favorable prognosis with low incidence of recurrence if excised with clear margins. Following complete excision, the patient is doing well.

PLEOMORPHIC LIPOMA: A RARE VARIANT OF LIPOMA IN AN UNUSUAL CLINICAL PRESENTATION

A 57-year-old white female patient complaining of a 5-day painless smooth and pedunculated nodule covered by healthy oral mucosa at the lingual retromolar region was submitted to excisional biopsy. The differential clinical diagnoses comprised fibroma and fibrous hyperplasia. Histologic aspect revealed a benign neoplasia characterized by proliferation of mature adipocytes and spindle cells. These cells presented elongated nuclei and were arranged in small blocks through the fibrous connective tissue. The final diagnosis was pleomorphic lipoma. Oral lipoma is an uncommon mesenchymal neoplasia that usually affects the buccal mucosa and has a benign course without recurrence. The pleomorphic variant is a remarkably rare form of lipoma in oral mucosa, and most of these lesions were described in the tongue. The fusiform component of this lesion is similar to other lesions, requiring special attention at morphologic examination to exclude well-differentiated liposarcoma or immunohistochemical staining (CD34 e S100) to exclude other spindle cell lesions. A 57-year-old white female patient complaining of a 5-day painless smooth and pedunculated nodule covered by healthy oral mucosa at the lingual retromolar region was submitted to excisional biopsy. The differential clinical diagnoses comprised fibroma and fibrous hyperplasia. Histologic aspect revealed a benign neoplasia characterized by proliferation of mature adipocytes and spindle cells. These cells presented elongated nuclei and were arranged in small blocks through the fibrous connective tissue. The final diagnosis was pleomorphic lipoma. Oral lipoma is an uncommon mesenchymal neoplasia that usually affects the buccal mucosa and has a benign course without recurrence. The pleomorphic variant is a remarkably rare form of lipoma in oral mucosa, and most of these lesions were described in the tongue. The fusiform component of this lesion is similar to other lesions, requiring special attention at morphologic examination to exclude well-differentiated liposarcoma or immunohistochemical staining (CD34 e S100) to exclude other spindle cell lesions.

INTRAMUSCULAR VARIANT OF LIPOMA IN THE TONGUE: A CASE REPORT

Although 20% of lipomas occur in the head and neck, only 1% to 4% of these are in the oral cavity. Histologically, they are classified into simple lipomas, fibrolipomas, angiolipomas, pleomorphic lipomas, spindle cell lipomas, sialolipomas, atypical lipomas, and intramuscular or infiltrative lipomas. The objective of this work is to report a clinical case of intramuscular lipoma in the tongue, since it is an uncommon lesion and requires follow-up because of its greater potential for recurrence. Patient S.P.O.G. is 78 years old with a nodular lesion in the right border of tongue present for 5 years. The lesion had well-defined borders, soft consistency, mucosa-like staining, and absence of painful symptomatology. The treatment was performed as an excisional biopsy. The histopathologic examination reported intramuscular lipoma, presenting muscle fibers inside and at the periphery of the lesion. The patient continues in periodic follow-up. Although 20% of lipomas occur in the head and neck, only 1% to 4% of these are in the oral cavity. Histologically, they are classified into simple lipomas, fibrolipomas, angiolipomas, pleomorphic lipomas, spindle cell lipomas, sialolipomas, atypical lipomas, and intramuscular or infiltrative lipomas. The objective of this work is to report a clinical case of intramuscular lipoma in the tongue, since it is an uncommon lesion and requires follow-up because of its greater potential for recurrence. Patient S.P.O.G. is 78 years old with a nodular lesion in the right border of tongue present for 5 years. The lesion had well-defined borders, soft consistency, mucosa-like staining, and absence of painful symptomatology. The treatment was performed as an excisional biopsy. The histopathologic examination reported intramuscular lipoma, presenting muscle fibers inside and at the periphery of the lesion. The patient continues in periodic follow-up.

LIP OSTEOLIPOMA, CLINICAL AND SURGICAL MANAGEMENT OF AN INFREQUENT DISEASE

Lipomas are relatively infrequent mesenchymal benign neoplasms of oral soft tissues. A wide range of subtypes of lipomas have been previously described, including fibrolipoma, angiolipoma, pleomorphic lipoma, and osteolipoma. The aim of this study is to present a clinical case of an 83-year-old man with a painless labial mass of 20-year duration with a remarkable increase in the size of the lesion in the last 2 years. Oral examination revealed a yellowish and sessile mass located in the lower labial mucosa. The provisional diagnosis was a lipoma, but during its surgical excision, a cartilaginouslike tissue was noticed generating some doubts about our previous diagnosis. The histopathologic findings revealed mature adipocytes surrounding bone tissue and the final diagnosis was osteolipoma. The presence of bony calcifications within this tumor could be related to metaplastic changes during the evolution of the lesion. This rare presentation was previously reported with different oral locations.

A study on cytology of soft tissue spindle cell tumors with histopathological correlation wherever possible

Introduction: Spindle cell tumors constitute an important component of soft tissue tumors. Fine needle aspiration cytology provides a predictive diagnosis of type and nature of these neoplasms. Methods: This study was conducted for a period of four years. Results: A total of 124 cases were diagnosed as soft tissue spindle cell tumors cytologically. Of these, 86 (69.35%) cases were benign and 38 (30.64%) were malignant tumors. 52 cases were available for histopathological follow up of which 49 cases (94.23%) showed positive correlation. Though there are no specific tissue architectural patterns in cytological smears, they are helpful in providing predictive diagnosis of benign or malignant nature of the tumour and in many cases also of specific tumor type. However, histopathology is considered as “gold standard” in diagnosing spindle cell tumors. Ancillary techniques are helpful in providing definitive diagnosis thus increasing the diagnostic accuracy of FNAC. There were 2 false negative cases which were cytologically diagnosed as Schwannoma and Neurofibroma because of the presence of wavy spindle cells and blood but both cases were diagnosed as malignant peripheral nerve sheath tumor on histopathology. There was 1 false positive case cytologically diagnosed as malignant spindle cell tumor but histopathologically diagnosed as Pleomorphic lipoma. Conclusion: Cytological and histopathological correlation was available in 36 benign tumors and 16 malignant tumors. Among benign tumors, 94.44% (34 cases) showed positive correlation, 5.56% (2 cases) showed negative correlation. Whereas among malignant tumors, 93.75% (15 cases) showed positive correlation and 6.25% (1 case) showed negative correlation between cytologic and histopathologic diagnosis.

A case of pleomorphic lipoma of the palate

A case of pleomorphic lipoma of the palate

Primary Pleomorphic Lipoma of the Parotid Gland with Prominent Myxoid Change: Report of a Rare Case Mimicking Carcinoma Ex Pleomorphic Adenoma on Fine Needle Aspiration Cytology

We present a case of a primary 2.5cm pleomorphic lipoma of the right parotid gland with prominent myxoid change which on FNA displayed features that mimicked a carcinoma or sarcoma ex pleomorphic adenoma. The patient was a 79year old man with no oncological history or tumor elsewhere. On immunohistochemistry the neoplastic cells strongly expressed CD34. There was no expression of retinoblastoma protein, smooth muscle actin, S100-protein or cytokeratins (AE1/3 and CAM5.2). The Ki-67 proliferation index was low (< 2%). Fluorescence in situ hybridization was negative for MDM2 gene amplification.

Abstract 1571: Benign lipomatous lesions and liposarcomas have metabolic differences as identified in a high-resolution 1H and 31P MRS pilot study

Abstract Adipocytic tumors present a spectrum of neoplastic disease including benign lipomas, atypical lipomatous tumors (ALTs), and malignant liposarcomas. Liposarcomas are the most common soft tissue sarcoma, accounting for approximately 20% of all adult soft tissue sarcomas [1]. Some liposarcomas are suspected to arise through dedifferentiation of ALTs, a process that is not well understood. Pleomorphic liposarcomas are high-grade, aggressive tumors with high metastatic potential and overall 5-year survival rate of 20-30% [3]. Distinguishing high-grade liposarcomas from benign and atypical lipomatous tumors can be a diagnostic challenge with implications for surgical and clinical management. The rate of misdiagnosis is approximately 30–40% following radiological detection [4], and 7–17% on histological evaluation [5]. De-identified human surgical samples were collected from the Dept. of Orthopaedic Surgery, JHU, School of Medicine Baltimore, MD. One tissue specimen from a benign pleomorphic lipoma and two tissue specimens from a pleomorphic liposarcoma were examined using 1H and 31P magnetic resonance spectroscopy (MRS) on 750 MHz MR spectrometer. Dual phase solvent extraction was performed to obtain aqueous and lipid phase spectra. Metabolites were quantified and changes were reported in terms of percentage change compared to levels in pleomorphic lipoma set to 100%. Depletion in branched chain amino acids (-10%), tyrosine (-15%), phenylalanine (-25%), lactate (-45%), pyruvate (-35-50%), acetate (-5-25%), and elevation in alanine (40%), succinate (35-60%), glycine (400-500%), histidine (15-25%), glucose (100%), glutamine (50%), glutamate (75%), and myo-inositol (300%) were observed in pleomorphic liposarcoma. 31P MRS of the aqueous phase revealed high levels of phosphocholine in the pleomorphic liposarcoma as compared to the lipoma (not detected). MRS analysis of the lipid phase identified depletion in lipid (-65%, CH3 peak at 0.9 ppm was quantified) and an increase in phosphatidylethanolamine (75%) and phosphatidylcholine (30%). Visible variations in TAG glycerol backbone (4.2-4.3ppm) and -CH=CH- peaks from polyunsaturated fatty acids at 2.8ppm and 5.3ppm were also observed. We are currently analyzing additional samples from several types of sarcomas to expand this study. Our preliminary data support investigating the use of 1H and 31P MRS of liposarcomas for differentiation between subtypes.

Spindle cell lipoma and pleomorphic lipoma: a clinicopathologic analysis of 65 cases

Objective: To investigate the clinical and pathological features of spindle cell lipoma (SCL) and pleomorphic lipoma (PL) with emphasis on differential diagnosis. Methods: Sixty-five cases of SCL/PL from the archive of Department of Pathology, Fudan University Shanghai Cancer Center, from August of 2006 to June of 2017, were included in the study. Immunohistochemistry by EnVision method, MDM2 gene amplifycation and DDIT3 gene translocation by fluorescence in situ hybridization(FISH) were detected and the literature was reviewed. Results: There were 53 males and 12 females with age ranging from 26 to 82 years (mean, 57 years; median, 59 years). The majority of the lesions occurred in the neck/posterior neck/nuchal region, upper back and shoulder. A small percentage of lesions developed in the extremities, face and trunk, and rarely in the epiglottis, mediastinum, labium majus and perineum. Clinically, the tumor usually manifested as a slowly growing mass or nodule. It was often encapsulated, ranging from 1 to 13 cm (mean, 4.1 cm; median, 3.5 cm) in size. Microscopically, SCL was composed of mature adipose tissue, bland spindle cells and bright eosinophilic "ropey" collagen fibers that varied in proportion. Of 45 SCL, 28 cases (62.2%) were classical, 6 cases (13.3%) were myxoid, 5 cases (11.1%) were fat-poor, 3 cases (6.7%) were fat-free, and 3 cases (6.5%) were pseudoangiomatoid. PL showed similar features as SCL, but was characterized by the presence of scattered floret giant cells. Of 20 PL, 11 cases (55.0%) were classical, 6 cases (30.0%) were mixed SCL/PL, 3 cases (15.0%) were fat-free. Both SCL and PL contained scattered mast cells in the stroma. By immunohistochemistry, the spindle cells in SCL and the floret giant cells in PL showed strong positivity for CD34 (52/52, 100.0%), bcl-2 (24/26, 92.3%) and CD99 (6/6), whereas they were negative for S-100 protein and STAT6. FISH analysis of MDM2 (17 cases) and DDIT3 (4 cases) was negative in all cases. Follow-up information was available in 32 patients (3 to 96 months), with local recurrence in only one patient. Conclusions: SCL and PL belong to the same entity but may exhibit morphological disparities. Of note, the fat-poor and fat-free variants are easily mistaken for other mesenchymal tumors. Attention should be paid in their differential diagnosis.