Idiopathic pulmonary calcification and ossification in an elderly woman with a missed diagnosis of subarachnoid haemorrhage.

This is a case of idiopathic pulmonary calcification and ossification in a 70 year old with long-standing diabetes and hypertension. Thirteen years prior to her demise, she was first noticed to have multiple calcific deposits in her lungs on a chest X-ray film. She had no risk factors for soft tissue calcification and ossification. Histology of tissue from autopsy showed intraparenchymal pulmonary calcification and ossification with marrow elements. Idiopathic pulmonary calcification and ossification is rare. At autopsy, she was also found to have had bilateral subarachnoid haemorrhage (SAH), a diagnosis missed during clinical evaluation. We highlight the pertinent details in our patient's management that could have helped to prevent a missed diagnosis of SAH. Even though SAH occurs most commonly following head trauma, the more familiar medical use of SAH is for non-traumatic SAH occurring following a ruptured cerebral aneurysm. This patient had notable risk factors for cerebral aneurysm formation but an aneurysm was not identified at autopsy. The location of the blood high on the cerebral convexities further suggests a traumatic origin rather than a ruptured aneurysm. Heterotopic calcification and ossification (HO) is known to occur in the setting of severe neurologic disorders such as traumatic brain injury but the fact that the lung calcification in our patient predated the brain injury by over 10 years makes it unlikely for the HO to have been due to the brain trauma. Other organ pathologies found at autopsy include chromophobe renal cell carcinoma, renal papillary necrosis, lymphocytic thyroiditis, and seborrheic keratosis.