Intraosseous xanthoma of the mandible: A multi‐institutional case series with a literature review

A Case Report of Craniofacial Intraosseous Xanthoma in a Patient Seeking Facial Feminization Surgery

BACKGROUND

Fibrous dysplasia (FD) is a benign developmental disorder of the bone that causes normal skeletal tissue to be replaced by excess fibrous tissue and poorly differentiated osteoblasts. Intraosseous xanthomas are benign intraosseous tumor growths characterized microscopically by the presence of lipid-laden foamy histiocytes, often with cortical expansion or disruption. Although FD commonly occurs in craniofacial bones, primary intraosseous xanthomas of the skull or facial skeleton are extremely rare. Although 2 distinct conditions, each may be difficult to differentiate on CT imaging when occurring in the facial skeleton.

METHODS

We report a case of an incidental finding on craniofacial CT of a frontal bone lesion originally thought to be FD. The finding was in a 55-year-old transgender woman who was assigned male at birth before receiving multiprocedural facial feminization surgery.

RESULTS

The clinical features, radiological findings, and treatment are discussed. Postoperatively, the patient had no sequelae secondary to facial feminization surgery or to the orbital lesion biopsy procedure. Bone graft appeared stable on CT imaging, although FD did not appear to resolve completely.

CONCLUSIONS

Diagnosis of such lesions is challenging and may require both radiographic and histopathologic assessment. As in the case of this patient, intraosseous xanthomas may also be misdiagnosed as other benign lesions such as FD. In most known cases, surgical intervention leads to complete resolution without recurrence of the lesion.

Xanthoma of the Jaw Bones: Cases Series and Review of Literature

BACKGROUND

Intraosseous xanthomas are rare benign lesions sometimes associated with excess lipid production. Xanthoma of the jaw bones (XJB) was first reported in 1964, and fewer than 50 cases have been reported in the English literature to date. The etiopathogenesis of XJB is highly suggestive of a reactive process or a metabolic condition.

METHOD

Seven cases of XJBs were retrieved from the archives of 4 oral and maxillofacial pathology services. Clinical, radiographic and histopathologic features of all these cases were retrospectively analyzed. Immunohistochemical (IHC) stains for S100 and CD68 were performed.

RESULTS

All seven cases involved the mandible. Patients' age ranged between 13 and 69 years with an evenly distributed female to male ratio. One patient had a medical history of hyperlipidemia, but the medical and dental histories of the others were unremarkable. For most cases, XJB was an incidental finding discovered during routine radiographic examination. Swelling and cortical expansion were noted in a few cases. Radiographically, cases typically presented as either well-defined multilocular or unilocular lesions, which were either radiolucent or mixed radiolucent/radiopaque. All the lesions were treated with surgical curettage and no recurrence was observed during subsequent follow-ups. Each of the seven cases exhibited sheets of foamy macrophages. The diagnosis is established by exclusion of entities with overlapping microscopic features and involved correlation with the clinical, histological, radiographic and IHC profiles. Immunohistochemically, all the cases expressed diffuse positivity for CD68 and were negative for S100.

CONCLUSION

XJB is a rare lesion of unknown etiology, which may mimic other benign or reactive jaw lesions. Due to its rarity and the potential diagnostic challenges it presents, clinicians must remain vigilant and consider CXJ in their differential when assessing radiolucent jaw anomalies.

Primary Mandibular Condyle Xanthoma: Case Report and Literature Review

Bone xanthoma is a rare benign primary bone lesion histologically characterized by sheets of foamy cells which are macrophages with a cytoplasm filled with droplets of fat. It is usually associated with endocrine or metabolic diseases, in the absence of which the lesion is called primary xanthoma. Because of the lack of pathognomonic radiologic and clinical features, they require a differential diagnosis with a broad spectrum of lesions with a varying degree of malignant potential. We describe a case of primary mandibular xanthoma of a 16-year-old girl without typical cutaneous manifestations and alterations in lipid values. The temporomandibular joint involvement at the mandibular condyle is peculiar in the case described here. We present even a qualitative systematic review of the literature on primary xanthoma of the jaws in others to draw up treatment guidelines.

Primary xanthoma inferior to the right mandibular third molar and intraoral vertical ramus osteotomy

Intraosseous xanthoma of the mandible is a rare benign disorder. A 17-year-old male patient presented with a suspected abscess in the right mandibular third molar, detected on a panoramic radiograph. The patient had no history of systemic or lipid-related metabolic diseases and complained of no specific symptoms or pain. A radiographic examination revealed a heterogeneous radiolucency extending from the apical to the distal aspect of the right mandibular third molar tooth germ. The lesion measured 9×16×24 mm (antero-posterior×mediolateral×supero-inferior) and showed a relatively well-defined, multilocular, foamy appearance with hyperostotic borders spreading to the inferior alveolar nerve canal. After excisional biopsy, a diagnosis of central xanthoma was made. The lesion recurred, and intraoral vertical ramus osteotomy was done near the lesion. For the treatment of xanthoma of the mandible, extensive and delicate surgical treatment under general anesthesia should be considered.

Multifocal Xanthoma of Bone

We report a case of a 40-year-old woman with hyperlipidemia and associated multifocal xanthoma of bone requiring prophylactic fixation of her bilateral femurs. Although xanthomas of bone are themselves a benign process, their presence may indicate that the patient has poorly controlled lipids and is at an increased risk of cardiovascular disease. Lytic lesions may require prophylactic fixation to prevent pathologic fracture.

Right Parietal Skull Xanthoma Characterized as a Metastatic Deposit

BACKGROUND

Xanthomas are benign lipomatous deposits that can be found systemically in various tissues including bones. Their presence in the skull remains a rare entity. Despite their benign characteristics, imaging modalities are often unable to distinguish them from malignant lesions. This leads to a diagnostic dilemma in patients with underlying malignancy. This case report highlights such a case where clinical history of prostate cancer and image findings were concordant with that of metastatic deposit in the parietal skull region.

CASE DESCRIPTION

This 65-year-old gentleman was diagnosed with prostatic adenocarcinoma. During systemic workup for his tumor, he was found to have a right parietal skull lesion. Magnetic resonance imaging of the brain, as well as a bone scan, were consistent with that of a metastatic deposit. As treatment would be drastically affected by the diagnosis, an excision biopsy was performed. The histology was consistent with that of a bone xanthoma.

CONCLUSIONS

Xanthomas are benign lesions that can be seen deposited in appendicular and axial skeleton. Skull lesions are rare with most case descriptions focusing on their presence in the frontoorbital regions and mandible and temporal bone. They usually have a benign course but may present with symptoms due to localized mass effect. Surgical intervention and histologic diagnosis may still be required in these lesions due to their lack of imaging characteristics that confirm their diagnosis through noninvasive methods.

Primary Intraosseous Xanthomas of the Jaws: A Series of Six Cases Including an Example with Formation of Apoptosis-Related Hyaline Globules, So-Called "Thanatosomes"

Primary intraosseous xanthomas of the jaws (PIXJ) are rare and predominantly affect the posterior mandible (86%) of normolipemic patients, with a mean age of 30 years and no gender predilection. Clinically, PIXJ exhibit indolent biologic behavior; curettage is considered treatment of choice. Only 36 PIXJ have been reported. Apoptosis-related hyaline globules (HGs), also known as "thanatosomes", have not been previously reported in PIXJ. Cases diagnosed as xanthoma of bone were retrieved. Six cases fulfilling currently accepted criteria were identified and their clinicopathologic and immunohistochemical properties are presented herein. Mean age for PIXJ was 21.8 years (range = 12-33) and F:M ratio = 2:1. All cases presented as well-demarcated, unilocular or multilocular radiolucencies. Microscopically, PIXJ featured sheets of lipid-laden macrophages with eosinophilic or foamy cytoplasm. A secondary fibroblastic population lacking storiform pattern was evident in two cases. Adipocytes (3/6), peripheral neurovascular bundles (1/6), bone fragments (3/6) and dystrophic calcifications (3/6) were observed enclosed by the xanthoma cells. Notably, one case exhibited numerous, spherical, eosinophilic HGs containing apoptotic nuclei. PIXJ were consistently CD68(+) and negative for CD1α and S100. CD45 decorated lymphocytes and the membrane of foamy histiocytes. Xanthoma cells stained for lysozyme and plasma proteins including alpha-1 antitrypsin (AAT), IgG and IgA in one probed case. HGs were lysozyme(+), AAT(+), IgG(+), IgA(+), PAS(+) and diastase-resistant, and fuchsinophilic with Masson's trichrome. PIXJ represent infrequent, solitary, mandibular lesions with a predilection for the second and third decade of life. Thanatosomes associated with cell injury and death can be present in PIXJ.