Intradiploic Epidermoid Tumors of the Cranium: Case Report with Review of the Literature

A Case of Telangiectatic Osteosarcoma in the Frontal Bone

Telangiectatic osteosarcoma (TOS) is a subtype of osteosarcoma. TOS in the elderly and TOS in the skull are very rare. Here, we report a case of TOS in the frontal bone of an elderly patient. The patient was a 79-year-old woman who was identified as having a right frontal bone lesion. The patient was initially diagnosed with an intradiploic epidermoid cyst (IEC). A 60mm cystic lesion with bone destruction appeared 5 years later, which enlarged over 2 months. The fluid in the cyst seemed to be blood that had lost its clotting ability. Tumor and the surrounding tissue were resected. The postoperative course was favorable. Postoperative magnetic resonance imaging (MRI) showed no evidence of residual lesions. There was no metastases. Histopathologically, the cyst wall was composed of fibrous connective tissue and did not contain epithelial components. There were no skin appendages and keratinized tissues in the lesion. Based on these findings, the diagnosis changed to aneurysmal bone cyst (ABC). Subsequent immunohistochemical examinations confirmed that the MIB-1 index was 50% in some sections and there were atypical cells showing osteogenic properties in other sections. Based on these results, the patient was finally diagnosed with TOS. The differential diagnoses for cystic lesion presenting bone destruction include TOS, ABC, and IEC. In case of cystic lesion with bone destruction, early diagnosis based on histopathological study is important and complete resection with surrounding tissues is required, given the possibility of TOS.

Intraorbital Expansion of an Intradiploic Frontal Epidermoid Cyst: A Case Report and Short Review of the Literature

Patient: Male, 58-year-old

Final Diagnosis: Epidermoid cyst

Symptoms: Exophthalmos

Medication:—

Clinical Procedure: —

Specialty: Neurosurgery

Acute-onset diplopia from intracranial hypertension due to torcular herophili obstruction by an hemorrhagic intradiploic epidermoid cyst

BACKGROUND

Epidermoid cysts are benign slow-growing congenital lesions, constituting approximately 1% of all cranial tumors. Most of these lesions are located intradurally, while about 10-25% of them are located within the diploic spaces. Intradiploic epidermoid cysts are usually discovered incidentally and may remain asymptomatic for many years, but in rare instances, they may grow intracranially and produce brain compression. Sometimes, intradiploic epidermoid cysts may occlude the main cranial venous sinuses causing intracranial hypertension.

CASE DESCRIPTION

We present the case of a 24-year-old male harboring a paramedian right occipital intradiploic cyst with erosion of both outer and inner bony tables, which occluded the torcular herophili producing a worsening symptomatology with acute-onset diplopia from right sixth cranial nerve palsy; the patient also presented bilateral papilledema, but only reported mild headache and dizziness. Neuroradiological studies evidentiated a lesion compatible with intradiploic epidermoid cyst with intralesional hemorrhagic component, overlying and almost completely occluding the torcular herophili. Considering the fast worsening of symptomatology and the evidence of intracranial hypertension, the patient was operated on immediately after completion of clinical and radiological assessment. The lesion was radically removed with almost immediate reversal of signs and symptoms. Histopathology confirmed the diagnosis of epidermoid cyst with intralesional hemorrhagic components.

CONCLUSION

Intradiploic epidermoid cysts may cause intracranial hypertension by occlusion of main cranial venous sinuses; intralesional hemorrhage may act as precipitating factor in occlusion of the torcular herophili, producing rapidly worsening intracranial hypertension, which requires prompt surgical treatment to reverse symptomatology. Radical surgical resection is necessary to avoid recurrence.

Giant Intradiploic Epidermoid Cyst in the Occipital Bone: A Case Report

Epidermoid cysts are uncommon intracranial tumors. As one of the extradural types of epidermoid cysts, intradiploic epidermoid cysts are even rarer tumors and occur in any part of the skull. We herein report a rare case of a giant intradiploic epidermoid cyst of the occipital bone. A 57-year-old woman presented with a 1-year history of localized headache in the occipital area. CT and MRI showed an extradural mass measuring 50×70 mm in the occipital bone with bony destruction. The patient underwent surgical resection. The tumor was completely removed with its capsule. There was no extension to the intradural space. The pathological report confirmed that the tumor was an epidermoid cyst. Follow-up MRI 24 months after the operation showed no recurrence. The headache was well controlled without any medications. We report a rare case of intradiploic epidermoid cyst with clinical and radiologic features and surgical treatment. It is important to consider this diagnosis for a patient with persistent regional headache with or without a growing scalp mass.

Spectrum of lytic lesions of the skull: a pictorial essay

Abstract

Lytic lesions of the skull include a wide range of diseases, ranging from benign conditions such as arachnoid granulations or vascular lacunae, to aggressive malignant lesions such as lymphomas or metastases. An early and correct characterisation of the nature of the lesion is, therefore, crucial, in order to achieve a fast and appropriate treatment option. In this review, we present the radiological appearance of the most frequent lytic lesions of the skull, describing findings from different imaging modalities (plain X-rays, CT and MRI), with particular attention to diagnostic clues and differential diagnoses.

Teaching Points

• Osteolytic skull lesions may be challenging to diagnose.

• Association of different imaging techniques may aid image interpretation.

• Clinical information and extensive knowledge of possible differential diagnoses is essential.

• Some osteolytic tumours, although benign, may present as locally aggressive lesions.

• Malignant lesions require accurate staging, followed by variable treatment approaches.