A preoperative MRI demonstrated a mixed solid and cystic mass in the region of the posterior third ventricle, without visible normal pineal tissue, as well as mild acute obstructive hydrocephalus (Figure 1).

(A) Sagittal post-contrast T1W image shows a heterogeneously enhancing mass in the posterior third ventricle. No normal pineal tissue is visible. There is mass effect on the midbrain tectum and poor visualization of the cerebral aqueduct (white arrow). Note the normal size of the fourth ventricle (white arrowhead), in keeping with obstructive hydrocephalus. (B) Axial T2 image again shows the mass, with solid and cystic components (black arrow). There is transependymal edema surrounding the atria (black arrowheads), indicating the hydrocephalus is of recent onset.

Portions of the mass showed areas of mild intrinsic T1 signal hyperintensity before administration of IV contrast, and there was heterogeneous enhancement after contrast injection (Figure 2).

(A) Axial T1W image shows mildly hyperintense signal along the wall of one of the cystic components (white arrow). (B) Post-contrast axial T1W image shows enhancement of this area, as well as of the more solid anterior component (white arrowheads).

CT imaging showed a calcified component of the mass (Figure 3).

Axial noncontrast CT image shows a prominent irregular calcification (black arrow) within the posterior aspect of the mass.

There was no evidence of disseminated tumor in the remainder of the brain or on subsequent spine imaging.

The patient underwent surgical resection. Histologic analysis of the tumor found moderately cellular neoplastic proliferation of epithelial cells, arranged in both back-to-back and singly protruding papillae (Figure 4).

A histologic slide shows a characteristic papilla (center) covered by layers of large eosinophilic cells with pleomorphic nuclei (H&E 200X). Immunohistochemical staining (not shown) revealed cells that were positive for Cam 5.2 and AE1/AE3, particularly in papillary regions, confirming epithelial origin.

Images: M. Ghesani, MD

Discussion

Pineal gland tumors are uncommon and account for less than 1% of all intracranial neoplasms.

Papillary components are a rare histologic feature of these tumors, but they can occur in a variety of pineal gland neoplasms that include choroid plexus tumor, pineocytoma, primary germ cell tumor, meningioma, papillary carcinoma and papillary ependymoma.

Papillary tumor of the pineal region (PTPR) was classified as a distinct entity by the World Health Organization in 2007. As of June, only 72 cases had been reported.

Histologic features that distinguish PTPR from other tumors with papillary features include rosettes and pseudorosettes. PTPR does not yet have defined histological grading criteria; however, most correspond to WHO grade 2 and the more aggressive examples correspond to WHO grade 3.

Presenting symptoms are nonspecific and may be secondary to obstructive hydrocephalus, including headache, gait imbalance, fatigue and memory loss. The age of presentation is variable. Thus far, the patients are aged 5 to 67 years, with a mean age of 34 years and a median age of 30 years. There also is a slight female predominance.

CT imaging features include a hyperdense or isodense mass in the pineal, with variable presence of calcifications. MRI features include a heterogeneous mass in the pineal region with small cystic spaces, components with intrinsically hyperintense T1 signal, and heterogeneous contrast enhancement.

The intrinsic T1 signal hyperintensity may be due to proteinaceous content of the cystic spaces. This feature of PTPR is nonspecific, as other pineal gland tumors may exhibit similar T1 signal characteristics. However, the use of fat-saturated and gradient echo sequences can narrow the differential by excluding fat-containing lesions (teratoma, dermoid, lipoma) and hemorrhagic metastatic disease. Data on perfusion, diffusion and proton spectroscopy are currently limited.

Treatment guidelines have not yet been developed due to limited data on the natural history of the disease.

Although local recurrence appears to be frequent, spinal metastases reportedly have been rare. Some groups have recommended surgical resection followed by adjuvant radiotherapy. There have been patients who also have received systemic chemotherapy with various combinations of cisplatin, etoposide, nimustine and ifosfamide; however, the exact role for adjuvant therapy has yet to be defined.

Five-year survival rates for patients have been reported to be 73.8%, and 10-year survival rates have been reported to be 61.5%.

Due to its tendency for local recurrence, serial imaging of the entire cerebrospinal axis has been recommended. Treatment guidelines would benefit from multicenter studies and long-term data.

Munir Ghesani, MD, is an attending radiologist at St. Luke’s-Roosevelt Hospital Center and Beth Israel Medical Center, an associate clinical professor of radiology at Columbia University College of Physicians and Surgeons, and a HemOnc Today section editor. Chun-Der Li, MD, Shain Wallis, DO, Ali Noor, MD, and Lauren Moomjian, MD, are residents in radiology at St. Luke’s-Roosevelt Hospital Center. Yinghua Pang, MD, is a resident in pathology at St. Luke’s-Roosevelt Hospital Center. Francisco Delara, MD, and Daniel E. Meltzer, MD, are attending radiologists at St. Luke’s-Roosevelt Hospital Center and Beth Israel Medical Center. They both are assistant professors of radiology at Albert Einstein College of Medicine of Yeshiva University. Disclosure: Drs. Ghesani, Li, Wallis, Noor, Moomjian, Pang, Delara and Meltzer report no relevant financial disclosures.

For more information:

Chang AH. Am J Neuroradiol. 2008;29;187-189.

Epari S. Neurol India. 2011;59:455-460.

Lechapt-Zalcman E. Neuropathol Appl Neurobiol. 2011;37:431-435.

Poulgrain K. J Clin Neurosci. 2011;18:1007-1017.

Vaghela V. Neurol India.2010;58:928-932.