Atypical Extraoral Presentation of a Heterotopic Gastrointestinal Cyst on the Face: A Case Report.

Heterotopias and choristomas are congenital lesions characterized by the presence of histologically normal tissues at non-physiological anatomic sites. The presence of gastrointestinal tissue in the oral cavity has been recognized as a heterotopic gastrointestinal cyst (HGIC) of the oral cavity. An intestinal heterotopia on the face, in relation to the parotid gland, is extremely rare. Highlighting this possibility is the case of a 42-year-old, non-habitué female with swelling in the parotid region of the face for two years. Clinical examination and radiographic investigations ruled out the possibility of a salivary gland tumor, epidermal inclusion cyst, and enlarged parotid lymph node while confirming the cystic nature of the presenting pathology. Further evaluation was carried out using an excisional biopsy. Histopathological evaluation revealed a cystic space lined by simple columnar epithelium with an abundance of goblet cells. The cystic epithelium was noted to form finger-like projections and crypts. An eosinophilic mucinous content was noted in the cystic space. Using Alcian blue-periodic acid-Schiff (PAS) staining, a distinct Alcian blue positivity of the mucinous material and the goblet cells was noted. This feature confirms the acidic nature of the mucinous content being liberated by the goblet cells. The histopathological features, along with histochemical assessment, were confirmatory for the diagnosis of an HGIC. The patient remains disease-free at the end of a 12-month follow-up. This is the first report of an HGIC at an extraoral site on the face in association with the parotid gland. It highlights the possible presentation of heterotopias in adult patients and warrants clinicopathological vigilance due to its benign nature and late presentation.