Dural-based Mass, Solitary

Miral D. Jhaveri, MD

DIFFERENTIAL DIAGNOSIS

Common

Epidural Hematoma
Meningioma
Metastases, Meningeal
Neurosarcoid
Lymphoma, Metastatic, Intracranial
Empyema

Less Common

Tuberculosis
Meningioma, Atypical and Malignant
Benign Nonmeningothelial Tumors
Malignant Nonmeningothelial Tumors
Langerhans Cell Histiocytosis
Plasmacytoma
Neuroblastoma, Metastatic
Leukemia

Rare but Important

Pseudotumor, Intracranial
Hypertrophic Pachymeningitis
Extramedullary Hematopoiesis
Rosai-Dorfman Disease
Neurocutaneous Melanosis (Melanocytoma/Melanoma)
Fibro-Osseous Lesion (Calcifying Pseudoneoplasm)

ESSENTIAL INFORMATION

Key Differential Diagnosis Issues

Any focal dura or arachnoid-based pathology can appear as an extra-axial mass abutting the dura, buckling/displacing cortex inwards
Epidural hematoma, meningioma are most common
“Dural tail sign” nonspecific, can be seen with many dural-based masses
Clinical history plays an important part in narrowing the differentials
In cases other than classic meningiomas dural biopsy is often essential to confirm the diagnosis

Helpful Clues for Common Diagnoses

Epidural Hematoma
- Hyperdense biconvex extra-axial mass on NECT (acute phase)
- Does not cross sutures unless sutural diastasis/fracture present, can cross falx & tentorium
- Trauma history, calvarial fracture in 85-95%
Meningioma
- Hyperostosis, cortical irregularity, calcification, peritumoral edema, trapped CSF clefts common
- Best imaging tool: MR + contrast
- 95% enhance homogeneously & intensely, dural tail often present
- MRS: Elevated alanine
Metastases, Meningeal
- Multiple > solitary lesions
- Skull often but not always infiltrated
- Often known extracranial primary neoplasm
Neurosarcoid
- 5% present as solitary dural-based extra-axial mass
- Presence of associated leptomeningeal enhancement additional clue
- Abnormal CXR, labs (increase ESR, ACE levels)
Lymphoma, Metastatic, Intracranial
- Localized dural mass mimicking meningioma
- 10-30% of patients with systemic lymphoma may develop secondary CNS involvement
- Leptomeningeal, parenchymal involvement more common
Empyema
- Extra-axial fluid collection with rim-enhancement & restricted diffusion
- Look for paranasal sinus or mastoid disease

Helpful Clues for Less Common Diagnoses

Tuberculosis
- Giant tuberculoma may mimic meningioma
- Abnormal CXR, lab values
- Travel history to endemic areas, immunocompromised
- MRS: Elevated lipid/lactate
Meningioma, Atypical and Malignant
- Dural-based lesion locally invasive with areas of necrosis & marked brain edema
- Indistinct tumor margins, may extend into brain, skull, scalp
- Biopsy is essential
Benign Nonmeningothelial Tumors
- Lesions of dura, skull, skull base, NECT best diagnostic tool
- Chondroma: Expansile, lobulated, curvilinear matrix calcification, mild enhancement
- Osteochondroma: Stalk is contiguous with the parent bone intramedullary marrow, may see calcified matrix in cap atop cortical bone
- Osteoma: Round dense lesion of the inner or outer table (outer table more common), no enhancement, no diploic involvement
Malignant Nonmeningothelial Tumors
- Highly aggressive dural, skull, scalp lesions invading locally
- Biopsy is essential
Langerhans Cell Histiocytosis
- Well-defined lytic skull lesion, beveled edge, associated dural & scalp soft tissue
- Younger age group
Plasmacytoma
- Solitary dural mass in patient with multiple myeloma, mimics meningioma
- Skeletal survey may help
Neuroblastoma, Metastatic
- Age < 5, known extracranial disease, calvarial-based mass, often around orbit/sphenoid wings
- NECT: “Hair-on-end” spiculated periostitis
Leukemia
- May present with or mimic hematoma
- Homogeneously enhancing extra-axial tumor(s) in patient with known or suspected myeloproliferative disorder

Helpful Clues for Rare Diagnoses

Pseudotumor, Intracranial
- Enhancing, infiltrating meningeal mass
- Predilection for meninges of cavernous sinus area or basal meninges
- Intracranial involvement in absence of orbital disease is rule (> 90%)
Extramedullary Hematopoiesis
- Patients with chronic anemia or marrow depletion
- Multiple > solitary
- Lobulated, homogeneous
- Mimics subdural hematoma on NECT
- Strong homogeneous enhancement
Rosai-Dorfman Disease
- Sinus histiocytosis with massive lymphadenopathy
- Multiple > solitary
- Mimics meningiomatosis, sarcoid, extramedullary hematopoiesis

SELECTED REFERENCES

1. Sahin F et al: Dural plasmacytoma mimicking meningioma in a patient with multiple myeloma. J Clin Neurosci. 13(2):259-61, 2006

2. Richiello A et al: Dural metastasis mimicking falx meningioma. Case report. J Neurosurg Sci. 47(3):167-71; discussion 171, 2003

3. Goldsher D et al: Dural “tail” associated with meningiomas on Gd-DTPA-enhanced MR images: characteristics, differential diagnostic value, and possible implications for treatment. Radiology. 176(2):447-50, 1990

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