A 36-year-old woman presented with left-sided exophthalmos. She first noticed proptosis about nine months before presentation. She had tearing and difficulty completely closing her left eyelid. She denied double vision, change in vision, or orbital pain. Past medical history included cervical cancer ten years prior. On physical exam, an ill-defined swelling lateral to the left orbit was appreciated. Her vision was intact and extraocular movements were normal. An MRI (Image A) and CT scan with contrast (Image B) revealed a largely osseous mass involving the lateral superior portion of the orbit and infiltrating the masseter and temporalis muscles.
Zygoma and greater wing of sphenoid
Whole Slide Image
The whole slide image provided is an H&E-stained slide of the sphenoid-zygoma mass from an excision.
What is the best diagnosis?
Metastatic cervical carcinoma
Solitary fibrous tumor/hemangiopericytoma
Which of the following IHC markers is most reliably positive in solitary fibrous tumor/hemangiopericytoma?
What is the most probable clinical concern for this neoplasm after surgical excision?
Development of similar lesions in other bones
Local recurrence and infiltration
Progression to higher grade
Transition to osteosarcoma
Discussion and Diagnosis
The diagnosis for this case is intraosseous meningioma. Meningiomas are the most common primary intracranial neoplasms. While they usually occur in association with the dura, up to 2% arise in other sites, and intraosseous meningiomas constitute about two-thirds of these. Those developing in bone, typically the skull, are designated intraosseous meningiomas. There is no typical appearance for intraosseous meningiomas on imaging studies. They may produce focal hyperostosis, lytic lesions, or, as in this case, both osteoblastic and osteolytic areas. Similarly, there is no single clinical presentation for this type of meningioma. Patient complaints and clinical findings depend on tumor location. In this case, the clinical differential diagnosis included metastatic cervical cancer, a sarcoma of bone or muscle, or some other locally-arising malignancy. Intraosseous meningioma was not clinically considered.
The histological characteristics and grading of intraosseous meningiomas are the same as those for dural-based tumors. As demonstrated in the H&E photomicrographs (Image C, Image D, and Image E), this meningothelial meningioma arises in bone and infiltrates adjacent muscle. Approximately 90% of nondural/extracranial meningiomas are WHO grade I tumors, and the majority are of meningothelial type. Tumor cells are strongly positive for epithelial membrane antigen (Image F) and show nuclear positivity for progesterone receptor (Image G). A possible pathogenetic role for progesterone has been postulated in numerous studies and may account for the higher incidence of meningiomas in women. As expected in a WHO grade I meningioma, the Ki-67 cell proliferative index (Image H) is relatively low. While most meningiomas are negative for cytokeratin (Image I), the cells surrounding pseudopsammoma bodies in the secretory variant are usually positive for both CEA and cytokeratin. CD34 (Image J) and STAT6 (Image K) stains are negative in this case, ruling out a diagnosis of solitary fibrous tumor/hemangiopericytoma. Unlike solitary fibrous tumor/hemangiopericytoma, meningiomas lack nuclear staining for STAT6, though they will occasionally show cytoplasmic positivity. Finally, somatostatin receptor type 2A (SSTR2A) (Image L) is emerging as a reliable marker for meningioma, and its use is increasing.
In most cases of intraosseous meningioma the treatment of choice is total surgical excision, if possible. While they do not show any increased propensity toward malignant transformation, intraosseous meningiomas tend to recur and infiltrate locally when subtotally removed. Such complications often occur when the tumor involves the orbit or closely juxtaposes vital structures.
Intraosseous meningioma, WHO grade I
Take Home Points
- Primary extradural meningiomas constitute up to 2% of all meningiomas, and intraosseous meningiomas constitute about two-thirds of these.
- Intraosseous meningiomas are characterized and graded using the same criteria as dural-based meningiomas.
- The majority of intraosseous meningiomas are of the meningothelial type, but other histological variants can occur.
- Intraosseous meningiomas may mimic a number of other neoplasms on MRI or CT studies, and thus are difficult to diagnose prior to excision.
- Chen TC. Primary intraosseous meningioma. Neurosurg Clin N Am. 2016;27:189-93.
- Elder JB, Atkinson R, Zee C-S, Chen TC. Primary intraosseous meningioma. Neurosurg Focus. 2007;23:e13.
- Liu Y, Wang H, Shao H, Wang C. Primary extradural meningiomas in head: a report of 19 cases and review of literature. Int J Clin Exp Pathol. 2015;8:5624-32.
- Perry A, Louis DN, Budka H, et al. Meningioma. In: Louis DN, Ohgaki H, Wiestler OD, et al, eds. WHO Classification of Tumours of the Central Nervous System. Revised 4th ed. Lyon, France: IARC; 2016:232-45.
- Perry A. Tumours of the meninges. In: Love S, Budka H, Ironside JW, Perry A, eds. Greenfield’s Neuropathology. 9th ed. Boca Raton: CRC Press; 2015:1803-27.
- Menke JR, Raleigh DR, Gown AM, Thomas S, Perry A, Tihan T. Somatostatin receptor 2a is a more sensitive diagnostic marker of meningioma than epithelial membrane antigen. Acta Neuropathol. 2015 Sep;130(3):441-3.
- Rushing EJ, Bouffard JP, McCall S, et al. Primary extracranial meningiomas: an analysis of 146 cases. Head Neck Pathol. 2009;3:116-30.
- What is the best diagnosis?
- A. Fibrous dysplasia
- B. Intraosseous meningioma
- C. Metastatic cervical carcinoma
- D. Osteogenic sarcoma
- E. Solitary fibrous tumor/hemangiopericytoma
- Which of the following IHC markers is most reliably positive in solitary fibrous tumor/hemangiopericytoma?
- A. Cytokeratin AE1/AE3
- B. Desmin
- C. EMA
- D. Progesterone receptor
- E. STAT6
- What is the most probable clinical concern for this neoplasm after surgical excision?
- A. Development of similar lesions in other bones
- B. Local recurrence and infiltration
- C. Progression to higher grade
- D. Systemic metastases
- E. Transition to osteosarcoma