Goblet Cell Adenocarcinoma With Heterotopic Ossification: A Rare Case Report and Review of Literature.

Heterotopic bone formation is a rare phenomenon when associated with gastrointestinal neoplasms. Here we present a rare case of heterotopic ossification associated with goblet cell adenocarcinoma of the appendix, and a literature review of such cases associated with neoplasms within and out of the gastrointestinal tracts. We reviewed the clinical data and when available, immunohistochemical markers of osteoblastic differentiation. Our review shows similar findings to prior reports of apparent high association of heterotopic bone formation with neoplasms with mucinous features. Two, previously proposed main hypotheses of the mechanisms are reviewed. The unique feature about this case is that goblet cell adenocarcinoma was not reported previously in the setting of bone formation.