Pineal parenchymal tumour with intermediate differentiation
Pineal parenchymal tumours with intermediate differentiation (PPTID) are, as the name suggests, tumours which fall between pineocytoma (well differentiated, WHO grade I) and pineoblastomas (poorly differentiated, WHO grade IV). They are considered WHO grade II or III tumours 2. Although these tumours are encountered at all ages, they are particularly seen in middle age adults (20-70 years of age) with slight female predilection, similar to that of pineocytomas 4.
Their radiographic appearance and biological behaviour are also intermediate. They may invade adjacent structures and also spread along CSF and therefore imaging of the entire craniospinal axis is therefore required 3.
Pineal parenchymal tumours with intermediate differentiation have a similar macroscopic appearance to pineocytomas, appearing relatively well circumscribed with heterogeneous cut surface 4.
Two microscopic patterns are encountered, sometimes co-existing 4:
The lobulated pattern, poorly defined lobules are separated from each other by large fibrous vessels 4.
When faced with a well-circumscribed pineal tumour with appearances of a pineocytoma, fairly rapid growth and/or low ADC values are clues that it may, in fact, represents a pineal parenchymal tumour with intermediate differentiation.
Treatment and prognosis
- 1. Prayson Richard A. and Mark L. Cohen. Practical differential diagnosis in surgical neuropathology. Humana Press, 2000. ISBN: 0896038173, 9780896038172.
- 2. Dumrongpisutikul N, Intrapiromkul J, Yousem DM. Distinguishing between germinomas and pineal cell tumors on MR imaging. AJNR Am J Neuroradiol. 2011;33 (3): 550-5. AJNR Am J Neuroradiol (abstract) - doi:10.3174/ajnr.A2806 - Pubmed citation
- 3. Smith AB, Rushing EJ, Smirniotopoulos JG. From the archives of the AFIP: lesions of the pineal region: radiologic-pathologic correlation. Radiographics. 2010;30 (7): 2001-20. Radiographics (full text) - doi:10.1148/rg.307105131 - Pubmed citation
- 4. Louis DN, Ohgaki H, Wiestler OD, Cavenee WK "WHO Classification of Tumours of the Central Nervous System. 4th Edition Revised" ISBN: 9789283244929
Pineal region masses
The pineal region is anatomically complex and plays host to a number of unique masses and tumours as well as potentially affected by many entities seen more frequently elsewhere in the brain.
- cystic non-neoplastic lesions
- pineal parenchymal tumours
- germ cell tumours
- tumours also encountered in the pineal region
- pineal gland metastases
- vascular lesions