Paraneoplastic Sensory Neuronopathy (PSN) may develop in patients with a number of underlying malignancies. It is caused by lymphocytic inflammation affecting neurons of the dorsal root ganglia (dorsal root ganglionitis).


Underlying malignancies may include:

(1) small cell lung cancer (SCLC), often associated with anti-Hu antibodies

(2) breast cancer

(3) other visceral carcinomas


Clinical features:

(1) pain including lancinating pain

(2) progressive sensory loss involving trunk, extremities and face, eventually resulting in complete sensory loss

(3) The patient may initially complain of tingling, burning and/or a cold sensation

(4) The patient develops disorganized movements and ataxia as various sensory inputs become impaired.

(5) Over time there is a loss of all tendon reflexes.

(6) Variable sensorineural hearing loss.

(7) Variable loss in the sense of taste (ageusia).

(8) The patient may also develop autonomic dysfunction.


Motor involvement should be absent.


Diagnosis may be challenging if:

(1) the findings are slowly progressive and asymmetric.

(2) the onset precedes diagnosis of the underlying cancer


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