Uncommon Etiology of Pulmonary Metastases Presenting as Hemoptysis

Abstract

INTRODUCTION: Basal Cell Adenocarcinoma (BCAC) is a relatively rare malignancy, accounting for approximately 2% of all salivary neoplasms. BCAC can occasionally cause invasive disease and infrequently, metastatic disease. Most common sites of metastases in BCAC include cervical lymph nodes with sparse reports of pulmonary, hepatic and cutaneous involvement. Here, we present a case of endobronchial metastases from BCAC of the base of the tongue. CASE PRESENTATION: A 76 y.o. male with a past medical history of BCAC who underwent right tongue base excision followed by adjuvant radiotherapy in 2018 who presented with a one-day history of hemoptysis. Two weeks prior to presentation, he underwent a CT-guided lung biopsy for a right upper lobe nodule that was nondiagnostic. He was then transferred to an academic medical center for further evaluation.On presentation, he felt well overall and had not experienced any additional occurrences of hemoptysis. CT chest revealed enlarging mediastinal lymph nodes causing severe stenosis of the bronchus intermedius and right lower lobe bronchus.On hospital day 2, he underwent bronchoscopy that revealed involvement of the bronchus intermedius resulting in approximately 80% luminal compromise. Tumor debulking and tracheal stenting was performed. Following discharge, PET scan confirmed malignant involvement. Pathology revealed a basaloid epithelial neoplasm morphologically similar to the prior tongue biopsy. Histology revealed an exceptionally high proliferation index (Ki67 > 90%). The decision was made to pursue palliative radiotherapy followed by pembrolizumab monotherapy. The patient expired approximately two months after diagnosis. DISCUSSION:The management of BCAC, as with all salivary gland neoplasms, is particularly challenging due to the phenotypic heterogeneity and low clinical incidence. The most common strategy includes surgical resection with adjuvant radiotherapy. While distant metastases is an uncommon recurrence, local recurrence is quite common despite tumor-free surgical margins with rates of upward to 50%. Chemotherapy has been found to be of limited use, predominately in the setting of recurrent or metastatic disease. Currently, there are no National Comprehensive Care Network (NCCN) recommendations for specific regimens. The most common agents include cisplatin, doxorubicin with either 5-fluorouracil or cyclophosphamide. However, no regimen has produced significant and reproducible improvements in overall survival or disease-free survival.CONCLUSIONS: This case demonstrates several unique features. This patient did not experience local recurrence, but rather distant metastasis to a novel location. Also, this patient featured an exceptionally high proliferation index, indicating that BCAC has the potential for clinical heterogeneity. Finally, this case highlights the need for further research into the role of imaging surveillance during remission.