A Case of Nasopharyngeal Pleomorphic Lipoma

We describe the presentation and treatment of the first reported case of a nasopharyngeal pleomorphic lipoma. The mass was successfully treated with a combined endoscopic trans-oral surgical excision approach by using low temperature-controlled plasma technology, resulting in optimal patient outcomes. Laryngoscope, 134:2710-2712, 2024.

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.

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.

Histopathologic and Genetic Findings in Atypical Spindle Cell/Pleomorphic Lipomatous Tumors and Atypical Pleomorphic Fibromas

BACKGROUND

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) that encompasses tumors in this spectrum that show atypical histopathologic features. We have observed PFs that show similar atypical features.

METHODS

Cases of SCL/PL and PF with atypical features were collected from tissue archives between 2010-2019. Genetic alterations were investigated using array comparative genomic hybridization (aCGH).

RESULT

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.

CONCLUSIONS

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.

A Diagnostic Dilemma in Fine-Needle Aspiration Cytology: Spindle Cell/Pleomorphic Lipoma

Pleomorphic lipoma is an uncommon, pseudosarcomatous lesion. It is characterized by the pleomorphic appearance on cytology and histology, follows a benign course, with a low rate of recurrence after complete excision, and has no risk of metastasis. Here, we describe a case of pleomorphic lipoma/spindle cell lipoma in a 41-year-old man who presented with a slow-growing mass on the inner aspect of the left thigh. On fine-needle aspiration cytology, it was reported as a cellular nerve sheath tumour followed by a wide excision sample sent for histopathological examination, which revealed spindle cells exhibiting pleomorphism with mature adipocytic cells and multinucleated floret cells in a myxoid background. It was reported as pleomorphic lipoma on histological examination.

Transoral robotic resection of unusual spindle cell/pleomorphic lipoma of the larynx

Spindle cell/pleomorphic lipoma (SC/PL) is a subcutaneous mass usually localised on nape, shoulder or upper back. It is a benign lipogenic tumour composed of primitive CD34-positive spindle cells, floret-like multinucleated giant cells and mature adipocytes. Complete surgical excision is the optimal treatment. This unusual tumour in the larynx has only been reported in the medical literature once and was treated surgically by open approach. Actually, transoral robotic surgery (TORS) is most suitable because provides tridimensional magnified view plus a greater mobility with instruments, allowing complete and safe removal of the supraglottic mass, allowing rapid healing and recovery. We present the first case of a SC/PL of larynx managed with TORS. Four hours after surgery, the patient was able to take a soft diet and was discharged 2 h later. The follow-up showed an excellent clinical and functional outcome.

Pleomorphic Lipoma of the Neck in an Infant: A Rare Clinical Entity

Lipomas are rare in the pediatric age group. A 10-month-old male child presented with an asymptomatic neck mass which was evaluated and excised completely. Histopathology was consistent with pleomorphic lipoma, not previously reported in children.

Loss of retinoblastoma in pleomorphic fibroma: An immunohistochemical and genomic analysis

BACKGROUND

Pleomorphic fibroma is a curious neoplasm that exhibits striking cytologic atypia, yet behaves in benign fashion. The cytologic features include single cells with pleomorphic nuclei and scattered giant cells resembling the neoplastic cells of pleomorphic lipoma, a tumor with known retinoblastoma (Rb) loss.

METHODS

We assessed the demographic and histopathologic features of a cohort of 26 pleomorphic fibromas, including assessment with immunostaining for Rb, p16 and Ki-67. Array comparative genomic hybridization (aCGH) was used to assess a limited number of tumors for genomic aberrations.

RESULTS

Of the 26 pleomorphic fibromas analyzed, 19 occurred in women and 7 in men, with a mean age of 47 years. The anatomic locations were variable. Immunostaining showed loss of Rb protein expression in all cases and diffuse p16 expression in 85%. Ki-67 labeling rate was below 10% in 85%. Chromosome 13q loss was found in 7 of 7 pleomorphic fibromas assessed with aCGH. Recurrent loss of 17p, 16q and 10q were also found.

CONCLUSION

We report recurrent loss of RB1 on chromosome 13q in pleomorphic fibromas, confirmed by both protein expression loss and loss of 13q by aCGH. This result indicates pleomorphic fibroma shares the same genetic abnormalities as spindle cell and pleomorphic lipomas.

Pleomorphic lipoma: A gentle giant of pathology

Pleomorphic lipoma is a relatively rare adipocytic neoplasm, occurring predominantly in elderly males in the subcutaneous tissues of the neck or shoulder. To the best of our knowledge, only five cases have been reported in which the lesion was intramuscular. We hereby report a case of a 60-year-old female patient, presenting with an intramuscular, posterior shoulder mass. The aspirate showed a giant cell-rich lesion, admixed with short, plump-looking, spindly cells. There was no overt evidence of malignancy; however, the cell cytology was sufficiently atypical to warrant concern. Subsequent excision revealed a classical pleomorphic lipoma on histology with no evidence of malignancy. CD34 staining by immunohistochemistry further supported the diagnosis. Differential diagnosis and the cytological diagnostic pitfalls of pleomorphic lipomas have been discussed with a review of the literature.

Pleomorphic lipoma of the tongue as potential mimic of liposarcoma

We herein report a rare case of pleomorphic lipoma of the tongue with a review of world literature. A 44-year-old woman presented with a nodule of the tongue that had been present for over three years. Clinical examination revealed a yellowish sub-mucosal lesion, measuring 3 cm in maximum diameter, protruding from lingual surface. A first biopsy showed a lipomatous tumour composed of mature adipocytes intermingled with myxoid areas composed of spindle uniform in size and shape and multinucleated floret-like giant cells. Spindle and giant cells were positive for CD34. A diagnosis of pleomorphic lipoma was made. In view of the benign nature of this mass, it was de-bulked rather than completely excised in order to preserve swallowing function.