Pineal parenchymal tumor of intermediate differentiation
Citation, DOI & article data
Pineal parenchymal tumors of intermediate differentiation (PPTID) are, as the name suggests, tumors that fall between pineocytoma (well-differentiated, WHO grade 1) and pineoblastomas (poorly differentiated, WHO grade 4). They are considered WHO grade 2 or 3 tumors 4. Their radiographic appearance and biological behavior are also intermediate.
Although these tumors are encountered at all ages, they are particularly seen in middle-aged adults (20-70 years of age) with slight female predilection, similar to that of pineocytomas 4.
Pineal parenchymal tumors 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:
In the lobulated pattern, poorly defined lobules are separated from each other by large fibrous vessels 4.
When faced with a well-circumscribed pineal tumor with appearances of a pineocytoma, fairly rapid growth and/or low ADC values are clues that it may, in fact, represents a pineal parenchymal tumor with intermediate differentiation.
As these tumors may invade adjacent structures and also spread along CSF and therefore imaging of the entire craniospinal axis is therefore required 3.
Treatment and prognosis
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- 4. Hasselblatt M, Huang A, Vasiljevic A, Jones DTW, Orr BA, Snuderl M, Pineal parenchymal tumour of intermediate differentiation. In: WHO Classification of Tumours Editorial Board. Central nervous system tumours. Lyon (France): International Agency for Research on Cancer; 2021. (WHO classification of tumours series, 5th ed.; vol. 6). https://publications.iarc.fr/601