Hydrancephaly is a rare condition where the brain's cerebral hemispheres are absent and the cranial vault is filled with fluid. It results from occlusion of the bilateral internal carotid or middle cerebral arteries, leading to liquefaction of brain tissue in the affected arterial territories while sparing structures supplied by the posterior circulation. Diagnostically, hydrancephaly is characterized by the absence of the cortical mantle with normal brain parenchyma replaced by liquefied tissue lined by leptomeninges, while the cerebellum and brain stem are usually intact. The prognosis is poor, with most infants dying within the first year of life.

1. HYDRANCEPHALY HYDROCEPHALIC ANENCEPHALY, HYDROENCEPHALODYSPLASIA, HYDROMERCENCEPHALY, CYSTENCEPHALY MERCURY IMAGING INSTITUTE SCO 172-173 SEC 9C CHANDIGARH MERCURY IMAGING CENTRE SCO 16-17 SEC 20D CHANDIGARH

2. HYDRANENCEPHALY ETIOLOGY Occlusion of Bilateral ICA Supraclinoid part or MCA on either side. Infection sequael Diffuse hypoxic ishemicsequael. Thromboblastic material from the deceased co twin DIAGNOSTIC FEATURES Cortical mantle abscent Normal brain parenchyma is liquefied and lined by leptomeninges. Basal ganglia / brain stem intact ( may be atrophic). Cerebellum intact in most of the cases. (Primarily structures supplied with Posterior circulation).

3. OCCLUSION OF SUPRACLIONID ICA -ACL / MCL LEADING TO LIQUEFACTION OF BRAIN IN THE MENTIONED ARTERIAL TERRITORIES SPARING OF PCL AND TERRITORY SUPPLIE.D BY IT

4. FALX INTACT / HYPOPLASTIC CEREBELLUM INTACT BRAIN STEM – INTACT / HYPOPLASTIC THALAMI – USUALLY INTACT. NO CORTICAL MANTLE BRAIN STEM INTACT THALAMI INTACCT LIQUEFIED BRAIN WITH LEPTOMENINGES LINING

5. DIFFERENTIALS In all the mentioned cases cortical mantle is preserved. Hydrancephaly – Liquefied brain lined with leptomeninges. Hydrocephalus : Csf lining is of ependyma. DIFFERENTIALS Extreme Hydrocephalus Alobarholoprosencephaly Severe form of porencephaly

6. Hydro is water compressing the brain, as noted on the brain.Hydra is the existence of water, where brain matter is non existent. Most patients do however have a brain stem allowing them to function normally. The prognosis is that a slim percent will see their first birthday. The majority of babies born with this disorder, expire.

7. PRESENT CASE 2 & ½ MONTH MALE CHILD WITH MACROCRANIA

8. INTACT CEREBELLUM/ATROPHIC BRAIN STEM LIQUEFACTION OF THE BRAIN PARENCHYMA

9. NO CORTICAL MANTLE PERIPHERAL MENINGEAL COVERING SEEN IHF INTACT

10. NO CORTICAL MANTLE PERIPHERAL MENINGEAL COVERING PRESENT CEREBELLUM INTACT BRAINSTEM PRESENT

11. VAULT SECTIONS IHF PRESENT