Table 2 Differential diagnosis of skull vault lesions

Osteoma

Osteomas are slow-growing lesions that are normally completely asymptomatic. A few may be associated with Gardner syndrome

CT: small, well-defined round, or oval dense and homogeneous lesions; homogeneous low signal intensity on T1WI; variable appearance on T2WI; not enhance after gadolinium administration

Not require surgical treatment unless the location or size of the lesion affects the adjacent structures (orbit, sinus, brain)

Aneurysmal bone cyst

Mainly in children and adolescents; may be secondary to other underlying lesions like fibrous dysplasia, chondroblastoma, and osteosarcoma

Sharply defined expanded osteolytic lesion with thin sclerotic borders, although the tables appear disrupted when the expansion is significant

The traditional treatment is complete surgical excision

Myeloma

Bone pain, deterioration of health, or abnormalities on blood or urinary test (e.g., high erythrocyte sedimentation rate, anemia)

Multiple small, roundish osteolytic lesions that are relatively uniform in size with sharp and non-sclerotic margins. On MRI, the signal intensity of the lesions is nonspecific; a “salt and pepper” appearance or diffuse bone marrow replacement may be noted

Treatment depends on the stage of the disease. The most common treatments are based on chemotherapy or grafting of hematopoietic cells

Langerhans histiocytosis

Clinical features are variable, from asymptomatic lesions to painful swellings

CT: unequal involvement of the inner and outer tables; appearance of having beveled edges. The lesion center may contain a sequestrum, representing residual intact bone. MRI: usually strongly enhance after gadolinium administration

Single lesions: conservative treatment (surveillance or systemic corticosteroids). More diffuse or aggressive forms: surgical excision, radiotherapy, and chemotherapy

Skull metastasis

Usually secondary to the breast, lung, prostate, kidney, and thyroid cancer; generally asymptomatic; may be revealed by a painful swelling

Mostly multiple, well circumscribed osteolytic lesions, which generally extend into the adjacent soft tissues. Usually homogeneously enhanced on enhanced MRI, but heterogeneous enhancement, peripheral ring enhancement, or lack of enhancement (sclerotic lesions) can be observed

Surgical treatment may be possible when there is only 1 metastasis, especially if without any neoplastic context. Radiotherapy is another alternative

Intraosseous meningioma

Predominantly seen in women in the fifth and sixth decades of life and often revealed by painless and expanded swelling

CT: osteosclerotic lesion with destructive irregular and spiculated borders. Low signal intensity on T1WI; variable signal intensity on T2WI; not enhance. Meningeal enhancement is rare and is explained by adjacent dural irritation or invasion, but the center of the tumor growth is outside the dura

Surgical resection of the lesion is required. The therapeutic decision depends on the possibility of resecting the lesion and on the patient’s health

Epidermoid and dermoid cyst

Painless subcutaneous swelling; discovered mainly during the third and fourth decades; predominantly occur laterally in the parietal or frontal bone

CT: well-demarcated osteolytic lesions with sclerotic borders; may tend to expand into both the inner and outer tables; homogeneously hypodense. MRI: fluid-like signal intensity on T1WI and T2WI and high signal intensity on DWI; usually do not enhance

Treatment of these cystic lesions is surgical, usually without recurrence