The inherited diagnosis and diagnostic error: a case report

We describe a case of diagnostic error arising from unquestioned acceptance of a longstanding, inherited diagnosis.

A patient developed CSF hypotension syndrome following minor trauma. A sacral cyst on imaging was attributed to a Tarlov cyst documented incidentally a decade earlier. Despite progressive symptoms, exhausted conservative therapy, and a radiological report explicitly questioning the diagnosis, the recommended post-myelography CT was twice deferred. The correct diagnosis - a meningomyelocele causing a traumatic CSF leak - was eventually established through external specialist consultation and treated surgically.

Diagnostic momentum, a non-integrated radiological correction signal, and the low cognitive accessibility of rare alternative possibilities combined to delay recognition of the meningomyelocele. Clinicians should not consider prior diagnostic labels as invariably true or well established. Many of these were simply never fully verified or confirmed over time, and these 'inherited' diagnoses are a risk factor for diagnostic error.