Match each patient's clinical presentation of a suspected paraneoplastic syndrome with the most likely underlying neoplastic etiology and its associated pathophysiologic mechanism.
- A 65-year-old man with a significant smoking history presents with new-onset proximal muscle weakness that improves with repeated exercise, accompanied by absent deep tendon reflexes.Small cell lung carcinoma; mediated by autoantibodies against presynaptic voltage-gated calcium channels.
- A 58-year-old woman with a palpable abdominal mass presents with recurrent episodes of facial flushing, frequent watery diarrhea, and a newly detected right-sided heart murmur.Metastatic midgut neuroendocrine tumor; mediated by excessive systemic secretion of serotonin and vasoactive peptides.
- A 70-year-old man with unintentional weight loss and vague abdominal pain develops recurrent, migratory superficial thrombophlebitis affecting multiple extremities.Pancreatic adenocarcinoma; mediated by tumor-derived mucins and tissue factor activating the coagulation cascade.
- A 50-year-old woman with a known adnexal mass presents with rapidly progressive cerebellar ataxia, dysarthria, and nystagmus over the past three weeks.Ovarian or breast carcinoma; mediated by cross-reacting anti-Yo (PCA-1) autoantibodies targeting Purkinje cells.
Answer
Lambert-Eaton syndrome matches with small cell lung carcinoma (presynaptic calcium channel antibodies); Carcinoid syndrome matches with metastatic neuroendocrine tumor (serotonin/vasoactive peptides); Trousseau syndrome matches with pancreatic adenocarcinoma (mucins/tissue factor); Paraneoplastic cerebellar degeneration matches with ovarian/breast carcinoma (anti-Yo antibodies).
Paraneoplastic syndromes represent systemic manifestations of cancer that are not directly caused by the physical mass of the primary tumor or its metastases. Understanding these pathophysiologic connections is essential for early diagnosis and appropriate management. Lambert-Eaton is driven by presynaptic voltage-gated calcium channel antibodies (small cell lung cancer); carcinoid syndrome by serotonin and vasoactive peptides (metastatic neuroendocrine tumors); Trousseau syndrome by tumor-derived procoagulants (pancreatic adenocarcinoma); and paraneoplastic cerebellar degeneration by cross-reacting anti-Yo antibodies (ovarian/breast cancer).
Step-by-Step Solution
Key Concept
Paraneoplastic syndromes often provide early clinical clues to an underlying malignancy and are mediated by aberrant tumor secretion of hormones, peptides, or cross-reacting autoantibodies.