Paraneoplastic Pseudoachalasia: An Uncommon Presentation of Malignancy

Abstract

Achalasia is an idiopathic disorder characterized by absent esophageal contractility and failure of lower esophageal sphincter relaxation. An identical clinical picture, termed pseudoachalasia, can be caused by benign or malignant disease processes at the gastroesophageal (GE) junction, including peptic strictures, post-surgical changes, and tumors. Less commonly, pseudoachalasia can be a result of a paraneoplastic phenomenon. Here, we present a case of small cell lung cancer (SCLC) presenting as dysphagia secondary to paraneoplastic pseudoachalasia. A 64-year-old female with a 40 pack-year smoking history presented with 5 months of progressive dysphagia to both solids and liquids, associated with regurgitation and a 45-kg weight loss. She also noted upper and lower extremity weakness and paresthesias. A barium esophagram demonstrated a dilated esophagus with a ‘bird beak' appearance of the GE junction. Subsequent esophagogastroduodenoscopy (EGD) confirmed that the narrowing was functional and not from obstruction. High resolution impedance manometry showed impaired LES relaxation and panesophageal pressurization consistent with type 2 achalasia. A CT scan of the chest revealed a left hilar mass, and pathology obtained via transbronchial needle aspiration was consistent with SCLC. A paraneoplastic panel was positive for Anti-Neuronal Nuclear Antibody-1 (ANNA-1), as well as N- and P/Q-type voltage gated calcium channel (VGCC) antibodies. Neurologic investigation with electromyography showed both a peripheral neuropathy and myelopathy. She underwent EGD with botulinum toxin injection of the LES, with moderate improvement in her dysphagia, after which definitive therapy for SCLC with chemoradiation was initiated. Pseudoachalasia secondary to a paraneoplastic syndrome is a rare diagnosis. It has been associated with a wide range of malignancies including esophageal, gastric, prostate, and lung cancers, with non-SCLC more commonly seen than SCLC. Multiple auto-antibodies have been implicated, including ANNA-1 and N- and P/Q-type VGCC antibodies, but to our knowledge, the presence of all three antibodies simultaneously is a novel finding. While neurologic symptoms are most common, a minority of patients will initially present with gastrointestinal dysmotility, including achalasia. In these patients, testing for paraneoplastic auto-antibodies should be considered, and investigation for an underlying malignancy should be pursued.Figure: Barium esophagram demonstrating a dilated esophagus with a ‘bird beak' appearance of the GE junction.