Paraneoplastic Syndrome?

[rebelray]

My initial symptoms of sudden dizziness occurred in July 2006, when I felt as if I was experiencing a stroke. I continue to experience a tipsy, drunken feeling most of the time (not unlike the feeling one has after several glasses of wine).

In November 2007 I saw a neurologist and obtained a preliminary diagnosis of ataxia and downbeating nystagmus. An MRI with and without contrast was performed and the results were normal, showing no cerebellar degeneration or lesions suggesting MS, and no findings to support the preliminary diagnoses.

The neurologist's initial report (before the MRI) referenced possible 'remote effects of cancer' i.e. paraneoplastic syndrome.

Question: What is the typical course of a suspected paraneoplastic effects, i.e. how long is the 'incubation' period for paraneoplastic syndromes to manifest into active cancers?

It is my understanding that most paraneoplastic syndromes (in men) result in small-cell lung carcinomas, and non-Hodgkins lymphomas. I have no sypmptoms of any of these cancers (yet), but my family history may indicate that it is more of a possibility.

Here is my medical background:

Age: 48 year old male
5'8" 155#
Smoking history: 1 pack per day, Age 17-24
Cancer history (all on mother's side): Uncles, ages 50 and 80 (pancreatic cancer); grandmother: oral cancer. No cancer on father's side.

[Fernando Roque, MD]

Hi.  A paraneoplastic syndrome is a condition wherein signs and symptoms are produced by a tumor at sites which are distant from its primary location or that of its metastases.  By definition, a tumor (whether benign or malignant) should already be in existence by the time the paraneoplastic syndrome manifests itself.  So it's erroneous to speak of an "incubation period", because the syndrome itself is already a manifestation of the tumor's "activity".  It often happens that the tumor presents initially as a paraneoplastic syndrome, even before it can be detected by radiographic imaging procedures like CT scan or x-rays.  But non-visualization of the tumor is a function of the insensitivity of the imaging procedures, and does not mean that the tumor is "inactive" or "incubating".  With the advent of more sensitive tools like the PET scan, it is now easier to confirm the presence of the tumor causing the paraneoplastic syndrome.  

Likewise, small cell lung cancer or non-hodgkins lymphomas do not "result" from paraneoplastic syndromes.  These cancers are already present at the onset of the syndrome, albeit in an occult (hidden) form.

Paraneoplastic syndromes usually result from one of the following mechanisms:

1.  The tumor produces substances which exert hormone-like effects [example: small cell lung cancer producing adrenocorticotropic hormone (ACTH) or anti-diuretic hormone (ADH).]

2.  Symptoms are produced as a result of "host response" to the tumor.  Host response typically takes the form of production of antibodies to the tumor.  These antibodies can cross-react with normal body tissue (example: neurons in the brain), resulting in the syndrome.

From the symptoms you described, I think your neurologist is considering the syndrome called paraneoplastic cerebellar degeneration (PCD).  This syndrome happens when anti-tumor antibodies cross react with nerve cells in the cerebellum, causing dizziness, ataxia and nystagmus.  To confirm this diagnosis, two things need to be done: 1) prove the existence of an underlying tumor by visualizing it using a radiographic procedure (preferably PET scan), and 2) detect the presence of circulating anti-tumor antibodies (called anti-Yo, anti-Hu and anti-Ri) in the cerebrospinal fluid or in the serum.