Petrous apicitis and acute bacterial meningitis are uncommon in the present antibiotic era. The diagnosis of petrous apicitis is seldom considered unless there is cranial nerve palsy. A young child with aplasia cutis congenita presented with acute bacterial meningitis and an incidental opacified left mastoid in brain imaging. During the course, fever persisted, and high-resolution temporal bone imaging showed rapid progression to coalescent mastoiditis, petrous apicitis with erosions of tegmen tympani, and petrous apex. Other findings included bony dehiscences and thinning of left calvaria. Tympanomastoid exploration showed herniated brain and cerebrospinal fluid leak through tegmen tympani, which was closed with temporalis fascia graft. Herein, we report a rare presentation of petrous and tegmen erosion along with aplasia cutis congenita and discuss the challenges in diagnosis and management.