Osteolipoma: a rare tumor in the oral cavity

Parosteal Lipoma Overlying an Osteochondroma of the Hyoid Bone: A Case Report and Literature Review

Parosteal lipomas and osteochondromas of the head and neck are uncommon benign tumors, constituting a small fraction of lipoma and bone tumor cases. We present a unique case of a 66-year-old male with a parosteal lipoma overlying an osteochondroma in the anterior midline neck, causing dysphagia. Surgical excision confirmed the diagnosis, and a literature review revealed similar cases predominantly adjacent to the mandible or calvaria. This case emphasizes the need to have parosteal lipoma and osteochondroma on the differential diagnosis for patients presenting with a firm mass of the central neck, especially with a history of trauma. Laryngoscope, 134:2844-2847, 2024.

Osteolipoma of head and neck - a review

OBJECTIVE

Due to the rarity of osteolipoma, current knowledge and understanding of its' clinical presentation, management, radiological features, histological characteristics, and prognosis are lacking and can present a clinical conundrum to clinicians and histopathologist alike, given wide range of differential diagnoses. This paper aims to compile, analyse and present details to augment the available literature on osteolipoma in the head and neck.

METHODS

A comprehensive literature search on PUBMED/MEDLINE, EMBASE, CINAHL and Science Citation Index, Google scholar and Cochrane database for osteolipoma in head and neck was performed up to the 1st May 2021. Reference lists from the relevant articles were then inspected and cross-referenced and any other pertinent publications were added to the review.

RESULTS

A total of 38 cases were identified from the literature. The commonest sites of involvement within the head and neck region were the oral cavity in 21 (56.8%) patients, followed by the neck in 7 (19.0%) patients. 29 (78.4%) patients presented with soft tissue swelling or mass making it the most common presenting feature. All patients had the tumour excised surgically; of which 18 (48.6%) were excised via transoral approach and 6 (16.2%) via open transcervical approach including 1 lateral pharyngotomy. 12 papers documented long-term follow-ups (median 12 months) with no recurrence. Only 1 regrowth was reported after 5-years.

CONCLUSIONS

Osteolipoma is a rare soft tissue neoplasm which has a wide range differential diagnosis including malignant processes. Recognising this benign tumour through an awareness of presenting sign and symptoms, radiological features and histopathology findings is important for patient reassurance as well as avoiding unnecessary radical treatment.

Expression profiles of exosomal tRNA-derived fragments and their biological functions in lipomas

There is evidence that exosomes derived from the lipoma tissue (Exo-LT) have a stronger capacity to promote the proliferation and migration of adipose-derived stem cells (ADSCs) than those from the adipose tissue (Exo-AT). But the Exo-LT do not have a significant effect on the adipogenic differentiation of the ADSCs. Recently, certain exosomal tRNA-derived fragments (tRFs) have been shown to play a crucial role in the pathogenesis of certain tumors. Therefore, it is necessary to identify the differently expressed tRFs in Exo-LT to further elucidate their molecular functions in lipomas. High-throughput sequencing was performed to examine the tRFs and mRNAs from the all samples belonging to the Exo-LT and Exo-AT groups. Target prediction and bioinformatics analysis were performed to explore their downstream mRNAs and biological functions. In total, 456 differently expressed tRFs and tiRNAs were identified in the Exo-LT group, 12 of which were up-regulated and 12 were down-regulated, respectively. Notably, tRF-1001 was most obviously down-regulated and tRF-3004a was most obviously up-regulated in the Exo-LT group. Moreover, among the target genes of tRF-1001 and tRF-3004a, both JAG2 and VSIG4 were significantly down-regulated in the Exo-LT group, while WNT5A, COL1A1, and PPARGC1A were highly expressed in both the Exo-LT and Exo-AT groups. The significant down-regulation of JAG2 and VSIG4 in the Exo-LT group could be due to the fact that Exo-LT had a stronger capacity to promote the proliferation and migration of ADSCs compared to the Exo-AT. The high expression of WNT5A, COL1A1, and PPARGC1A in both the Exo-LT and Exo-AT groups could be due to the similar ability of Exo-LT and Exo-AT to promote the adipogenic differentiation of ADSCs.

Parosteal lipoma of the mandible: A case report and review of the literature

Introduction:

Lipomata are soft-tissue mesenchymal neoplasms that are benign in nature and often asymptomatic. Lipomata commonly occur in the body, however, only 1%–5% are identified within the oral cavity, and lipomata with osseous metaplasia account for <1% of all lipomata.

Materials and Methods:

A PubMed literature review designating search terms including “oral” and “parosteal lipoma” or “lipoma with osseous metaplasia” or “ossifying lipoma” or “osseous lipoma” was conducted.

Results:

The literature review identified two previous reports of parosteal localization of lipomata in the mandible and 22 cases of lipomata with osseous metaplasia within the oral cavity.

Conclusions:

With the initial suspicion of a more malevolent diagnosis, this rare entity, with only two other cases identified, is important to consider in the clinician's differential diagnoses.

Intraparotid Osteolipoma: Treatment Option and Surgical View

ABSTRACT

Osteolipoma is a benign neoplasm originating from the mesenchymal fat tissue cells and characterized by the presence of bone formation. In the head and neck district osteolipoma has been described as parapharyngeal, nasopharinx, submandibular gland, eyelid, floor of the mouth, and skull base lesion. Only 1 case of osteolipoma was reported as a neoplasm of the parotid region. Considering the rarity of the osteolipoma, our purpose was to describe the first case of totally intraparotid gland localization of osteolipoma and summarize and review the actual literature concerning the presence of this tumor in the region of major salivary glands. A 56-years-old male patient was treated for intraparotid osteolipoma. Surgical removal of tumor was done with a standard preauricular/cervical incision and blunt dissection. The facial nerve was identified and preserved completely. In the reviewed series, all cases were reported in adult patients with a relative long history of slow progression. According to our paper and the review of the literature, we can assess that Osteolipoma is an extremely rare lesion affecting the major salivary glands, which should be considered along with common salivary gland tumors in the differential diagnosis.

Osteolipoma: a review of the literature and a rare case report

OBJECTIVES

Lipomas are the most common benign mesenchymal tumors of soft tissue. According to previous studies, 1-4% of the cases has been observed in the oral cavity. A histological variant of lipoma featuring bone formation is called osteolipoma and has been very rarely observed (less than 1% of the total). In order to make a meaningful addition to this rare knowledge base, our study aims to provide a literature review and to report an additional case of osteolipoma.

METHODS

An electronic search in the PubMed database with the keyword "osteolipoma" was conducted. Among 69 search results, only the cases of osteolipoma located in the "oral cavity" were included in this study. The findings of the previously reported 20 cases (in English) of osteolipoma of the oral cavity were organized in a table along with a new case of osteolipoma located in the mandibular buccal vestibule with radiological and histopathological findings provided by the authors.

RESULTS

Osteolipoma affects both sexes and usually emerges in middle-aged or elderly patients with a long history of slow progression. Different imaging techniques may be utilized in the radiographic evaluation.

CONCLUSION

Differential diagnosis includes a wide range of lesions; therefore, the clinical and radiographic evaluation should be confirmed by histopathological examination. The suggested treatment is complete surgical excision and follow-up, and the prognosis is generally good.

Ossifying Lipoma in Costal Arches That Suggest Extensive Pulmonary Involvement: Case Report

Background:

Lipomas are the most common benign soft tissue tumors in the general population. These lesions can appear on any part of the body and usually develop in the subcutaneous superficial tissue. Lipomas that show ossifying changes are very rare, representing less than 1% of the reported lipomas. They usually manifest as hard nodular lesions in the head and neck, the extremities, the sternoclavicular region, and the subcutaneous tissue in general; they are rare in the costal arches.

Case presentation:

We report the case of a patient with a history of multiple diseases and 2 tumor-like lesions with internal lytic areas detected in the fourth right costal arch and in the eighth left costal arc; we describe his clinical manifestations, radiological and laboratory findings as well as the pathological results and outcome.

Conclusions:

Ossifying lipomas are rare benign tumors with asymptomatic clinical presentation. It is important to perform an adequate radiological differentiation from other more aggressive lesions such as liposarcomas.

Osteolipoma: An Extremely Rare Hard Palate Tumor

Lipoma and its variants rarely involve the oral cavity. Osteolipoma of the hard palate is extremely uncommon with only a few cases reported worldwide. It is important to recognize and give comprehensive diagnosis of this entity, so as to prevent unwarranted medical interventions. Here, in this report, we describe a rare case of osteolipoma arising in the hard palate of a 35-year-old male and the diagnostic conundrum associated with it. The approach to such a case, differential diagnosis, and review of the literature are also presented.

Investigation of stemness and multipotency of equine adipose-derived mesenchymal stem cells (ASCs) from different fat sources in comparison with lipoma

BACKGROUND

Adipose tissue-derived mesenchymal stem cells (ASCs) offer a promising cell source for therapeutic applications in musculoskeletal disorders. The appropriate selection of ASCs from various fat depots for cell-based therapy is challenging. The present study aims to compare stemness and multipotency of ASCs derived from retroperitoneal (RP), subcutaneous (SC), and lipoma (LP) fat to assess their usefulness for clinical application.

METHODS

Equine ASCs from the three fat tissue sources were isolated and characterized. The cell viability, proliferation, and self-renewal were evaluated using MTT, sulforhodamine B, and colony forming unit (CFU) assays. Stem cell relative marker CD44, CD90, and CD105 and tumor marker CA9 and osteopontin (OPN) expression were quantified using RT-qPCR. Multipotency of ASCs for adipogenic, osteogenic, and chondrogenic differentiation was examined by quantifying Oil Red O and Alizarin Red S staining, alkaline phosphatase activity (ALP), and expression of differentiation relative markers. All data were statistically analyzed using ANOVA.

RESULTS

RP fat-derived ASCs showed a higher cell proliferation rate compared to SC and LP derived cells. In contrast, ASCs from lipoma displayed a lower proliferation rate and impaired CFU capacities. The expression of CD44, CD90, and CD105 was upregulated in RP and SC derived cells but not in LP cells. RP fat-derived cells displayed a higher adipogenic potential compared to SC and LP cells. Although ASCs from all fat sources showed enhanced ALP activity following osteogenic differentiation, SC fat-derived cells revealed upregulated ALP and bone morphogenetic protein-2 expression together with a higher calcium deposition. We found an enhanced chondrogenic potency of RP and SC fat-derived cells as shown by Alcian blue staining and upregulation of aggrecan (Aggre), cartilage oligomeric matrix protein precursor (COMP), and collagen 2a1 (Col2a1) expression compared to LP. The expression of OPN and CA9 was exclusively upregulated in the ASCs of LP.

CONCLUSIONS

The results provide evidence of variation in ASC performance not only between normal fat depots but also compared to LP cells which suggest a different molecular regulation controlling the cell fate. These data provided are useful when considering a source for cell replacement therapy in equine veterinary medicine.

Calcified or ossified benign soft tissue lesions that may simulate malignancy

The purpose of this article is to review calcified or ossified benign soft tissue lesions that may simulate malignancy. We review the clinical presentations, locations, imaging characteristics, and differential diagnostic considerations of myositis ossificans, tophaceous gout, benign vascular lesions, calcific tendinopathy with osseous involvement, periosteal chondroma, primary synovial chondromatosis, Hoffa's disease, tumoral calcinosis, lipoma with metaplasia, calcifying aponeurotic fibroma, calcific myonecrosis, ancient schwannoma, and Castleman disease.

Stem Cells Derived from Lipoma and Adipose Tissue-Similar Mesenchymal Phenotype but Different Differentiation Capacity Governed by Distinct Molecular Signature

Lipomas are benign adipose tissue tumors of unknown etiology, which can vary in size, number, body localization and cell populations within the tissue. Lipoma-derived stem cells (LDSCs) are proposed as a potential tool in regenerative medicine and tissue engineering due to their similar characteristics with adipose-derived stem cells (ADSCs) reported so far. Our study is among the first giving detailed insights into the molecular signature and differences in the differentiation capacity of LDSCs in vitro compared to ADSCs. Mesenchymal stem cell phenotype was analyzed by gene expression and flow cytometric analysis of stem cell markers. Adipogenesis and osteogenesis were analyzed by microscopic analysis, cytochemical and immunocytochemical staining, gene and protein expression analyses. We showed that both LDSCs and ADSCs were mesenchymal stem cells with similar phenotype and stemness state but different molecular basis for potential differentiation. Adipogenesis-related genes expression pattern and presence of more mature adipocytes in ADSCs than in LDSCs after 21 days of adipogenic differentiation, indicated that differentiation capacity of LDSCs was significantly lower compared to ADSCs. Analysis of osteogenesis-related markers after 16 days of osteogenic differentiation revealed that both types of cells had characteristic osteoblast-like phenotype, but were at different stages of osteogenesis. Differences observed between LDSCs and ADSCs are probably due to the distinct molecular signature and their commitment in the tissue that governs their different capacity and fate during adipogenic and osteogenic induction in vitro despite their similar mesenchymal phenotype.