A Mandibular Metastasis as the Initial Presentation of Hepatoid Adenocarcinoma of the Lung: A Case Report.

Hepatoid adenocarcinoma of the lung is a rare primary pulmonary malignancy that exhibits morphological traits resembling those seen in hepatocellular carcinoma and is associated with high alpha-fetoprotein expression. It follows a very aggressive course and is often diagnosed in advanced oncologic stages. We present our experience with this malignancy and report on a case with mandibular metastasis, an uncommon metastatic site. The patient, a 64-year-old male smoker with an estimated 50-pack-year history, was evaluated for a solid lesion in the left upper lobe, accompanied by hypertrophic pulmonary osteoarthropathy. He had undergone right partial gnathectomy for a symptomatic metastasis to the right submandibular region with pathology indicating hepatoid adenocarcinoma. Imaging revealed a 35×33 mm lesion in the left lung without nodal metastasis. Surgical management included a left upper lobe lobectomy and associated mediastinal lymphadenectomy, and the final diagnosis of primary hepatoid adenocarcinoma of the lung with neuroendocrine differentiation was confirmed. Despite chemotherapy, the patient developed bony metastases and succumbed four months post-surgery. The above case highlights the aggressive nature of hepatoid adenocarcinoma, underscoring the importance of early diagnosis and the challenges posed by its metastatic spread. To our knowledge, this is the first reported instance of HAL presenting with mandibular metastasis as the initial manifestation, thereby expanding the known spectrum of metastatic sites.