New insights on fibrodysplasia ossificans progressiva: discussion of an autoptic case report and brief literature review.

Fibrodysplasia ossificans progressiva (FOP) is a rare genetic condition with soft tissue progressive ossification, leading to severe disability. We describe a 27-years-old female affected by FOP who died after a fall. An autopsy was performed. Upper and lower extremities resulted in fixed flexion, with kyphoscoliosis of the spine and chest wall deformity. Moreover, a cranial fracture was pointed out. At histology, atypical abundance of corpora amylacea in gray matter was observed. In a sample of macroscopically non-affected muscular tissue, small areas with necrosis of myocytes and hyperplasia of fibroblasts were seen in light microscopy, with intracellular inorganic dystrophic inclusions in transmission electron microscopy. Thyroid gland histology showed diffuse lymphocytic infiltration. Postmortem examination of FOP patients provided precious information about involvement of other tissues, suggesting an initial and widespread inflammatory/dystrophic phase, to be further investigated, because it might reveal new insights about a FOP mutation cascade.