Desmoplastic Infantile Astrocytoma and Desmoplastic Infantile Ganglioglioma – not so infantile anymore

Desmoplastic Infantile Astrocytoma and Desmoplastic Infantile Ganglioglioma – not so infantile anymore Sahai J.1*, Sahu S.2 DOI: https://doi.org/10.17511/jopm.2020.i07.05 1* Jyotsna Sahai, Resident, Department of Pathology, MGM Medical College and Hospital, Navi Mumbai, Maharashtra, India. 2 Shilpi Sahu, Professor and HOD, Department of Pathology, MGM Medical College and Hospital, Navi Mumbai, Maharashtra, India.


Introduction
The terms desmoplastic infantile astrocytoma (DIA) and desmoplastic infantile ganglioglioma (DIG) were coined by VandenBerg in 1987 based on immunohistochemistry and electron microscopy findings [1].
DIA and DIG are rare, massive, enhancing, supratentorial neoplasms that usually occur in children, before 2 years of age with a median of 6 months [2]. The WHO categorizes DIA / DIG as grade I "neuronal and mixed neuronal-glial" entity in its classification of Central Nervous System (CNS) neoplasms [3].
Before the WHO classification, DIA and DIG were thought to be separate entities. (4) But given their similar clinical, neuroimaging and pathological features, they were grouped together by WHO in 2000 [5,6]. The tumors invariably arise in the supratentorial region and commonly involve more than one lobe, preferentially the temporal and frontal lobes.
Neuroimaging studies reveal these neoplasms as large, hypodense cystic masses with a solid isodense or slightly hyperdense superficial portion along with dural attachment [7]. Grossly The lesion also caused a midline shift of 1.2 cm towards the left.

HISTOPATHOLOGICAL EXAMINATION
Gross specimen received was fragmented with multiple, grey-brown, soft to firm tissue pieces, the largest measuring 3.5 x 3 x 1.5 cm and the smallest measuring 1 x 1 x 0.5 cm.
Microscopically, a study of H and E stained sections The histomorphological features were suggestive of DIG, which was confirmed on further immunohistochemistry.
The IHC profile performed was as follows - The immunohistochemical markers confirmed the diagnosis of DIG.

CASE TWO
A 4-year-old girl presented to the surgery OPD with complaints of headache, repeated falls for two months along left-sided weakness for three days following a fall from the bed. CT scan showed a 5.8 x 5.2 x 5.5 cm sized heterodense, predominantly hyperdense lesion in the right frontoparietal lobe causing midline shift of 1.1 cm to left and also causing a mass effect on right lateral ventricle with specs of calcification and necrotic tissue within.
There was evidence of vasogenic edema and thinning of skull vault on the right side (right frontal bone). The radiological differential diagnoses were -

HISTOPATHOLOGICAL EXAMINATION
The gross specimen received was fragmented, well encapsulated, soft to firm with the larger piece measuring 7 x 4.5 x 4.3 cm, and the smaller one  Special stain Reticulin was positive.
The above findings were suggestive of the following differential diagnoses -Immunohistochemistry was performed to confirm the same. As shown in figures 9 -11, the IHC profile showed

Discussion
DIA and DIG are rare neuroepithelial, low grade, benign neoplasms usually occurring before the age of 24 months of life with boys being affected more than girls, and exceedingly rare in the older age group. Our study showed the occurrence of both cases in females and at a later age than usually found. Grossly, the tumors are usually massive as was seen in our cases also and are firmly attached to the dura, which was also seen in our cases. They are composed of two components, solid and cystic. On histopathological examination, they are wellcircumscribed and highly desmoplastic tumors.
The cell population is typically glial and / or neuronal The diagnosis is confirmed by immunohistochemistry, as was done in our cases.
These tumors stain positively for GFAP (Diffusely) and focally for synaptophysin (neuronal cells). The findings of our cases were similar to these with DIG showing positivity for GFAP, Synaptophysin whereas DIA showed diffuse positivity for GFAP and negative Synaptophysin (as it contained no neuronal elements).
These tumors have an indolent course and usually do not recur after complete resection, suggestive of a favorable prognosis. Our patients were followed up for 6 months and both are hale and hearty with no recurrence of tumors or complaints.

Conclusion
The two cases discussed above show that such cases can present later in life and vary from the usual presentation of DIA / DIG as thought so far and thus should always be kept in mind as a differential diagnosis when reporting CNS neoplasms. Tropical Journal of Pathology and Microbiology 2020;6(7)