Osteolipoma: An unusual tumor of the parotid region

Deep Cervical-thoracic Osteolipoma Near the Brachial Plexus - Case Report and Literature Review

Osteolipoma is a rare benign variant of lipoma and constitutes less than 1% of all lipomas, presenting as a well-circumscribed painless mass. It is a tumor known to occur in several regions, usually intraosseous or adjacent to bone tissue, whose pathogenesis is still unclear. Imaging exams are useful in their evaluation and, mainly, in surgical planning, which consists of tumor excision. However, the definitive diagnosis of osteolipoma is made by histopathological examination. Although benign, osteolipomas can compress surrounding structures, leading to important symptomatology, as in this case reported in which it is in contact with the brachial plexus.

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.

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.

[Parosteal osseous lipoma of the temporal bone concurrent with involvement of the parotid salivary gland]

The paper describes a case of parosteal lipoma of the temporal bone, by simultaneously involving the parotid salivary gland. Computed tomography performed in a 48-year-old man showed that in the area of the posterior edge of the glenoid fossa of the right temporal bone there was a massive (1.5×1.7×0.9-cm) exostosis extending down from the skull base. The exostosis was surrounded by a 3.5×3.6×5.3 soft tissue mass that was located in the projection of the right parotid salivary gland with a capsule and minor calcifications. Morphological examination determined a sessile exostosis-like mass in the area of the periosteum of the temporal bone. Foci of desmal and enchondral ossification (types III and IV according to the classification of Miller et al.) could be seen in the adjacent fatty tissue. The tumor underwent necrotic and dystrophic changes (Milgram's Stage 3). Temporal bone involvement was accompanied by osseous sialolipoma of the right parotid salivary gland. In this case, the fatty component accounted for 60-80% of salivary gland volume. Terminal secretory segments, ducts, and bone trabeculae with calcification foci and hematopoietic elements were uniformly distributed among the fatty tissue. None similar case has been found in the literature.

Osteolipoma of the buccal mucosa: a case report

Lipomas are benign mesenchymal neoplasms of soft tissue that can be found commonly in any part of the human body. Their presence in the oral mucosa is uncommon, however, with approximately 4% of the cases occurring in the oral cavity. Oral lipomas are likely to have originated from mature adipose tissue and there are several histological variants of lipomas described, which are identified according to the predominant type of tissue in addition to adipose tissue. A rare lipoma variant, known as an osteolipoma or an ossifying lipoma, may occur; however, little has been written this type of lipoma characterized by a classical lipoma with areas of osseous metaplasia. This paper describes a case of an osteolipoma involving the buccal mucosa of an adult patient.

Parosteal ossifying lipoma of the clavicle: A case report

Lipomas are very common benign adipose tissue tumors that most often develop in subcutaneous tissue. A limited number of studies have described the characteristics of parosteal ossifying lipomas located in the fibula, cervical vertebrae and mandible. However, to the best of our knowledge, parosteal ossifying lipoma of the clavicle has not yet been reported. We herein describe the clinical symptoms, radiological and histological findings in a rare case of parosteal ossifying lipoma of the clavicle in a 40-year-old male patient. The characteristic histological appearance, together with computed tomography and/or magnetic resonance imaging characteristics, should aid in the accurate diagnosis of such cases.

Bilateral hamartomatous medullary lipoma within the nasal turbinate bones in a cynomolgus monkey (Macaca fascicularis)

A 15-year-old male cynomolgus monkey (Macaca fascicularis) showed large bilateral masses in the maxillary sinus. In histopathological examination, both masses revealed benign medullary lipomas within the turbinate bones. The tumors were composed of well-developed lipocytes, trabecular bones and a few blood vessels. Although we initially diagnosed the tumor as bilateral lipomas in the nasal turbinates, it was not differentiated from lipomatous hamartoma. Findings, such as unique symmetrical proliferation, lack of border from the normal marrow and the intact surrounding tissue, indicated a lipomatous hamartoma/hamartomatous lipoma, thought to be a suitable diagnosis of the lesion. Of most interest was that such a proliferating lesion occurred in the nasal turbinate.

A huge osteolipoma involving the coronoid process: a case report

A 28-year-old man visited our hospital with the chief complaint of trismus. Computed tomography revealed a well-defined, soft tissue tumor, 66 × 45 × 21 mm, with a distinct boundary in the inner region of the zygomatic arch. The mass contained various sizes of bone-like hard tissue, some of which adhered to the right coronoid process. A contrast-enhanced magnetic resonance image showed that the mass was composed mainly of adipose tissue. Tumorectomy was performed, and the histopathological diagnosis was osteolipoma. At 2-year follow-up, mouth opening had increased from 31 mm to 50 mm. (J Oral Sci 58, 141-144, 2016).

Osteolipoma in the glabella: pathogenesis associated with mesenchymal lipoma-derived stem cells

Lipoma is a benign tumor that often arises in the craniomaxillofacial region. Osteolipoma containing bone tissue is very rare and the developmental mechanism is unclear. Mesenchymal stem cells in adipose tissue that have potential to differentiate into fat, bone, cartilage, and vascular components may be involved in the development of osteolipoma, in which adipose and bone tissues coexist. We encountered a patient with osteolipoma that arose in the glabella. We describe the case and the results of an investigation of the presence in lipomas of mesenchymal stem cells with differentiation potential similar to that of normal adipose cells. The patient was a 66-year-old woman. Histopathologically, bone tissue surrounded by fibrous connective tissue was present in the nodular adipose tissue and was diagnosed as osteolipoma. Mesenchymal stem cells were collected by collagenase treatment of lipoma tissue, and their potential to differentiate into fat, bone, and cartilage was shown. On the basis of this study, we suggest that lipoma-derived mesenchymal stem cells are the basis of the pathogenesis of osteolipoma. The conditions that induce differentiation of mesenchymal stem cells into bone remain to be investigated.

Fat-containing salivary gland tumors: a review

Fat-containing tumors of the salivary glands are uncommon. Their wide histological spectrum varies from pure lipomatous neoplasms similar to their cutaneous and soft tissue counterparts to mixed lipoepithelial lesions specific to the salivary glands. With few exceptions, these uncommon lesions affect mainly the elderly, with a mean age at presentation of ≥ 50 years and show a predilection for males. A few cases occur in childhood; some of them represent congenital lesions. In decreasing order of frequency, ordinary (soft-tissue type) lipoma, oncocytic lipoadenoma, non-oncocytic sialolipoma, and pleomorphic adenoma/myoepithelioma with extensive lipometaplasia are the main variants of fat containing tumors encountered in the salivary glands. While pleomorphic adenoma/myoepithelioma with lipometaplasia behave in the same way as their non-fat-containing counterparts, other lipomatous salivary gland tumors listed above are cured with simple excision and do not carry a risk of recurrence. Other lipoma variants (spindle cell lipoma, osteolipoma, fibrolipoma, angiolipoma, pleomorphic lipoma, lipoblastoma and hibernoma) are exceptionally rare in the salivary gland. Atypical lipomatous tumors/liposarcoma have been only rarely reported in the salivary gland and they behave in a similar fashion to their soft-tissue counterparts. Diffuse lipomatosis and lobular fatty atrophy are the two tumor-like lesions that might closely mimic sialolipoma, particularly in limited biopsy material without knowledge of the gross findings. This review summarizes the clinicopathological features of the main types of salivary fat-containing lesions and discusses their differential diagnoses.

Lipomatous lesions of the parotid gland: analysis of 70 cases

OBJECTIVES/HYPOTHESIS

To investigate presenting signs and symptoms, preoperative workup, operative therapy, and morbidity of benign and malignant lipomatous lesions of the parotid gland.

STUDY DESIGN

Medical literature review and retrospective chart review for all patients who underwent surgery for lipomatous lesions of the parotid gland at our institution from 1959 to 2009.

METHODS

Seventy patients underwent surgery for such lesions. Histologic sections were stained with hematoxylin-eosin and reviewed, and clinical information was obtained from hospital medical records for each case.

RESULTS

Forty-nine patients (70.0%) were male and 21 (30.0%) female (mean age, 49.9 years). Of the lesions, 43 (63.2%) were intraparotid, 25 (36.8%) periparotid, 69 (98.6%) unilateral, and 1 (1.4%) bilateral (average size, 3.7 cm). Fifty-nine patients were treated with superficial or partial superficial parotidectomy, 10 were treated with total parotidectomy, and one was treated with parapharyngeal space dissection. Complications included six cases (8.6%) of facial paresis or paralysis and two cases of hematoma. No lesions recurred.

CONCLUSIONS

We present the largest series, to our knowledge, of lipomatous lesions of the parotid gland. These masses, although rare, should be considered in the evaluation of a parotid mass. This series provides insight into the clinical presentation, diagnostic evaluation, and surgical treatment of parotid lipomatous lesions. Surgical extent depends on lesion location in the gland. Lipomatous masses can be effectively treated surgically with low morbidity and high cure rates.

Lipoma with bone and cartilage components in the left axilla of a middle-aged woman

Lipoma is the most common type of benign soft tissue tumor. However, lipoma containing bone or cartilage is very rare, especially a tumor containing both of these components. We encountered a 59-year-old woman who had a benign lipoma of the infraspinatus muscle that contained both osseous and chondral components. Histopathological examination revealed the presence of chondral and osseous elements mixed with mature adipose tissue. To the best of our knowledge, there has never been a report of benign lipoma containing osteochondral tissue at this location. Therefore, we report the first case of an axillary lipoma with bone and cartilage components.

LEVEL OF EVIDENCE V

This journal requires that authors assign a level of evidence to each article.

Osteochondrolipoma of the submandibular region: a case report and review of the literature

Lipoma is an extremely common and ubiquitous benign soft tissue tumor composed of mature adipose tissue, with frequent differentiation towards other mesenchymal elements such as blood vessels, fibrous tissue, or muscle. They are typically slow-growing, encapsulated, superficial or deep, and have a wide range in size depending on their location. The presence of cartilage or bone is very rare, with most reported cases in the head and neck area. We report the case of an osteochondrolipoma of the submandibular region with associated benign bone marrow elements, with a review of the literature and discussion of the differential diagnosis.