Paraneoplastic Syndrome: What should Pulmonologists know?

Takeshi Saraya*

Paraneoplastic Syndrome: What should Pulmonologists know?

Pulmonologists often encounter patients with oncologic emergencies such
as metabolic syndrome, hypercalcemia, syndrome of inappropriate secretion of antidiuretic hormone,
hematologic and structural disorders, along with drug-related adverse event sin already-known
malignancies including liver or pulmonary toxicity and renal disease.

Additionally, pulmonologists occasionally encounter paraneoplastic
syndrome, which partially overlaps with oncologic emergencies. In this regard,
pulmonologists should be aware of PNS, involving organ-based classification.

PNS has diverse symptoms and signs in neurologic, muscle/neuromuscular junction/skeletal,10 hematological, eye,
renal, metabolic, skin, and endocrine systems, which often present as antecedent problems of lung
cancer or other malignancies. In some cases, physicians might have difficulty in discriminating PNS from malignant independent conditions due to clinical
similarity but they are pathologically different.

PNS occurs in approximately 10% of patients with lung cancer, and the histology
of lung cancer influences the type of associated PNS. The most common forms
of PNS are hypercalcemia from squamous carcinoma and SIADH in small cell lung cancer.

Nowadays, various onconeural antibodies have been detected, and well-characterized autoantibodies such as anti-Hu, anti-Yo, anti-CV2, anti-Ri, anti-Ma2, and anti-amphiphysin have been described. Other partially
characterized onconeural antibodies and other antibodies were also identified.

These antibodies seem to be directly involved in cell surface or synaptic proteins
or disrupt function of receptors by cross-linking and internalization, which leads to PNS. Moreover, although identification of onconeural antibodies can be a useful marker for early diagnosis of PNS and/or malignancies,
multidisciplinary assessment for PNS is needed along with long-term observation.

Pulm Res Respir Med Open J. 2017; 4(2): e6-e8. doi: 10.17140/PRRMOJ-4-e009