Melanoma Metastasis to the Gastric Mucosa Preceded by Guillain-Barré as a Paraneoplastic Syndrome

Guillain-Barré is a rare disease, with an overall incidence of 1–2 per 100,000 yearly.^1,2 It may be associated with cancer—mainly Hodgkin lymphoma—but it is seldom found in the setting of metastatic cancer.³

Melanoma metastasis to the stomach mucosa is an even rarer phenomenon, with very few cases reported in the literature. We present a case of mucosal metastasis of melanoma that was preceded by swiftly evolving Guillain-Barré syndrome.

CASE REPORT

A 68-year-old, previously healthy patient began in May 2013 to have lower back pain that was nonresponsive to common analgesics. The patient sought medical care in his health care unit, but developed a symmetric, lower limb, rapidly progressive weakness that evolved into complete paraplegia a couple of days before any diagnosis was made and prompted his admission to the hospital. On physical examination, his deep tendon reflexes were absent, but his sensory functions were preserved.

Brain and medullar spine computed tomographic (CT) scans displayed no abnormalities, and a lumbar puncture showed elevated cerebrospinal fluid protein with a normal blood cell count. Electromyography showed acute polyneuropathy with predominant demyelinating features, consistent with a diagnosis of Guillain-Barré syndrome.

The patient denied any recent episode of infection, and test results for viral infections such as HIV were negative. He then underwent intravenous immune globulin treatment for 5 days, but the disease continued to progress, with the patient having difficulty in swallowing. An upper endoscopy was performed to install a jejunostomy feeding tube, during which an ulcerated, dark lesion was discovered in the gastric mucosa. (Figures 1–3). A biopsy was then performed, and metastatic melanoma was identified (Figure 4).

Figure 1.

Greater view: nodular lesion on the gastric mucosa.

Figure 2.

Lateral view: nodular lesion on the gastric mucosa with high borders and depressed, dark center.

Figure 3.

Closer view: nodular lesion on the gastric mucosa with eroded, depressed, dark center.

Figure 4.

Gastric mucosa infiltrated by a malignant neoplasm constituted by proliferating melanocytic cells with irregular, hyperchromatic, prominent nuclei and pigment production compatible with metastatic melanoma.

Concurrently, because the patient complained of bone pain, scintigraphy was undertaken and revealed multiple bone metastases. His performance status was very poor when he was referred to our oncology unit; hence, he was put into best supportive care and died 2 days later.

DISCUSSION

Melanoma rates in many countries are among the fastest rising of the solid malignancies.^4–6 In southern Brazil, which is populated largely by people with a European background (mainly German and Italian ancestries), the rate has increased exponentially during the past 30 years.⁷ Accordingly, the diagnostic methods have improved,⁸ but incidences are increasing among populations believed to be less likely to have access to screening services.⁹

The classic pattern of main sites of metastatic visceral involvement in melanoma is the central nervous system, lungs, and liver.^10,11 We have presented a case of advanced disease in an unusual location, preceded by a rare paraneoplastic syndrome. To our knowledge, it is the first ever reported case with this description. It must be acknowledged that the 2 conditions may not be related, even though the patient did not present any of the classic infections that can lead to Guillain-Barré syndrome. As diagnostic imaging and screening techniques continue to develop, we are likely to have more frequent diagnoses of “hidden” malignancies that are associated with a preceding paraneoplastic syndrome and could have gone unnoticed before such techniques were available.

During the patient's short hospital stay in the oncology unit, no primary lesion was found in his physical examination. A subclinical lesion or a nonexternal skin location may be among several reasons for the absence of a lesion. Likewise, we hypothesize that primary melanoma regression had occurred, an event known to be associated with poor prognosis¹² and compatible with a clinical picture of swiftly evolving disease that renders the location of the primary site impossible.

The arrival during the past few years of several drugs that prolong overall survival in advanced melanoma has opened a new era for patients and health care professionals.^13,14 We believe that, as patients continue to live longer, more and more metastases to unusual locations will be seen, a phenomenon already described in other types of cancer.^15,16