Mandibular metastasis in a patient with undiscovered synchronous thyroid and prostate cancer: A diagnostic dilemma

BACKGROUND: Mandibular metastasis as the first manifestation of undiscovered synchronous double primary cancers is extremely rare, so, it is presented in the current study. CASE HISTORY: This study reports a 73-year-old man, complaining of a painful mass in the mandible. After history taking, physical examination and panoramic radiographic evaluation; an incisional biopsy was performed intraorally. Histological studies revealed a metastatic tumor of epithelial origin with nonspecific primary site. During metastatic workup of the patient, it was accidentally found that three organs including prostate, lung and thyroid were involved with cancer. Using immunohistochemical study (prostate-specific antigen (PSA), thyroid transcription factor 1 (TTF-1) and thyroglobulin), a final diagnosis of thyroid carcinoma metastasis to the mandible was established. DISCUSSION: This case report showed that the practitioners should always maintain a high index of suspicion to the possibility that a patient with an orofacial metastatic lesion may have two or more synchronous primary cancers.