Review the following clinical vignettes describing patients who are experiencing complications related to underlying malignancies. Match each patient's clinical presentation with the primary pathophysiologic mechanism responsible for their symptoms.
- A 68-year-old man with a newly discovered right hilar mass presents with proximal muscle weakness that transiently improves with repetitive movement, accompanied by dry mouth and absent deep tendon reflexes.Cross-reactivity of tumor-directed autoantibodies with presynaptic voltage-gated calcium channels
- A 55-year-old woman with a history of treated breast cancer presents with subacute, rapidly progressive truncal ataxia, dysarthria, and multidirectional nystagmus. Brain magnetic resonance imaging reveals no intracranial metastases.Immune-mediated destruction of cerebellar Purkinje cells by onconeural antibodies
- A 42-year-old man with bulky mediastinal lymphadenopathy, fever, and drenching night sweats develops anasarca. Laboratory studies show a serum albumin of 2.1 g/dL and a 24-hour urine protein of 5.2 g.Release of T-cell-derived cytokines resulting in effacement of glomerular epithelial foot processes
- A 72-year-old man with an apical lung mass and a 50-pack-year smoking history presents with confusion, polyuria, and abdominal pain. Laboratory evaluation reveals a serum calcium of 14.2 mg/dL and an intact parathyroid hormone of 5 pg/mL.Ectopic secretion of a peptide that binds to and activates osteoblast parathyroid hormone 1 receptors
Cevap
Lambert-Eaton syndrome (hilar mass) matches with antibodies against presynaptic calcium channels. Paraneoplastic cerebellar degeneration (breast cancer) matches with immune destruction of Purkinje cells. Minimal change disease (mediastinal mass/Hodgkin lymphoma) matches with cytokine-mediated foot process effacement. Humoral hypercalcemia of malignancy (apical lung mass) matches with ectopic PTHrP secretion.
Each clinical vignette provides a classic presentation of a distinct paraneoplastic syndrome. The first is Lambert-Eaton myasthenic syndrome (LEMS) caused by anti-calcium channel antibodies. The second is paraneoplastic cerebellar degeneration caused by anti-Purkinje cell antibodies. The third is minimal change disease secondary to Hodgkin lymphoma, caused by cytokine-induced podocyte injury. The fourth is humoral hypercalcemia of malignancy caused by tumor secretion of PTHrP.
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Anahtar Kavram
Paraneoplastic syndromes possess specific pathophysiologic mechanisms that must be correlated with their associated underlying malignancies and varied clinical presentations.