Metastatic.html


    
        
            
                Metastatic melanoma to the small bowel complicated by fistula formation

            

            
                Nausheen Khan, MB BS, FC Rad 
            

            Irma van de Werke, MB ChB, FRCR
        

        Department of Radiology, Kalafong Hospital, Pretoria

        Zaeem I Ebrahim, MB BCh, FC Rad
    

    Farzanah Ismail, MB BCh, FC Rad


Department of Radiology, Steve Biko Academic Hospital and University of Pretoria


    Corresponding author: Z Ebrahim (zaeem@iafrica.com)




    Introduction

    Malignant melanoma (MM) is an unpredictable tumour
    that can metastasise to any organ, and is well known for its widespread
    dissemination. The incidence of metastases to the gastro-intestinal
    (GI) tract is well documented; this, however, is a late manifestation
    of the disease with an overall poor prognosis. Most GI metastases are
    asymptomatic and are only discovered on postmortem, with the majority
    in the small bowel. The presenting symptoms are usually of obstruction
    or intussusception; GI bleeding is also common. Fistula formation with
    the small bowel is rare; ours is believed to be the second case
    documented.1
    ,
    2


Case history

A 59-year-old man presented with a 2-month history
of change in bowel habits. There was no significant history of illness
in the past and no known primary lesion. Clinically, his abdomen was
distended with a palpable right iliac fossa mass extending to the
supra-pubic area. There were no signs of guarding or tenderness. Blood
tests showed that he was anaemic, with haemoglobin of 9.4g/dl,
leucocytosis and raised C-reactive protein (CRP).

Radiological findings

Ultrasound

Ultrasound showed a para-caecal mass associated
with para-aortic and para-pancreatic lymphadenopathy. Computed
tomography (CT) scans (Figs 1 - 3) revealed a large intraperitoneal,
predominantly mesenteric, mass in the right lower abdomen crossing to
the contra-lateral side, with a large central ulceration and fistula
formation with the distal small bowel i.e. ileum with an air contrast
level within the tumour. There was also para-aortic and peri-pancreatic
lymphadenopathy.The rest of the small bowel was displaced anteriorly,
and the sigmoid pushed postero-laterally.

Discussion

MM is one of the most common malignancies to metastasise to the GI tract.2  It does so via lymphatic channels to parenchymal organs. Symptomatic metastasis to the GI tract is seen only in 2% of patients.3 Metastases
may present at the time of primary diagnosis or decades later as the
first sign of recurrence. MM that involves the GI tract may be either
primary or metastatic.2 
Symptoms include abdominal pain, dysphagia, small bowel obstruction,
haematemesis and melena. Symptoms are usually identical to those caused
by primary GI tumours.4
,
6


Primary GI melanoma can arise in various GI mucosal
sites, including the oral cavity, oesophagus, small bowel, rectum and
anus, in the absence of prior cutaneous melanoma. Primary melanoma of
the GI tract is rarely diagnosed at an early stage. Distinguishing
between a primary GI mucosal melanoma and melanoma metastases to the GI
tract from an unknown or regressed cutaneous primary may be difficult.2
,
4


The most common sites of metastases are lymph nodes
(73%) and lung (71%), followed by the liver, brain, bone and adrenal
glands; GI metastasis stands at 43%. Superficial spreading melanoma is
the most common subtype to metastasise to the GI tract.2


Diagnosis of MM is generally made by radiographic
contrast studies, including CT, ultrasound and barium studies, as well
as endoscopic evaluation. Most recently, positron emission tomography -
computed tomography (PET/CT) has been used to identify sites of
metastatic melanoma. CT sensitivity is between 60 and 70%.2
,
5


Metastatic lesions may be intraluminal masses,
ulcerating lesions (as in our case), diffusely infiltrating lesions or
mesenteric implants.

Conclusion

MM in the GI tract is a late manifestation of the disease, with overall poor prognosis.6 
In a patient presenting with a GI tract mass, initial differentials
should include primary GI tract tumours as well as lymphoma; however, a
high index of suspicion for metastatic melanoma should be maintained if
the patient presents with seemingly unrelated symptoms or history of
treated melanoma in the past.

1. Casanova F, Lizazo J, Shezi S, Oliver F. Right inguinal bowel
fistula on the course of melanoma disease. Internet Journal of
Oncology. 2009;6(2).

1. Casanova F, Lizazo J, Shezi S, Oliver F. Right inguinal bowel
fistula on the course of melanoma disease. Internet Journal of
Oncology. 2009;6(2).

2. Liang KV, Sanderson SO, Nowakowski GS, Arora AS. Metastatic
malignant melanoma of the gastrointestinal tract. Mayo Clinic College
of Medicine. Mayo Clinic Proceedings 2006;81(4): 511-516.

2. Liang KV, Sanderson SO, Nowakowski GS, Arora AS. Metastatic
malignant melanoma of the gastrointestinal tract. Mayo Clinic College
of Medicine. Mayo Clinic Proceedings 2006;81(4): 511-516.

3. Tsilimparis N, Menenakos C, Rogalla P, Braumann C, Hartmann J.
Malignant melanoma metastasis as a cause of small bowel perforation.
Onkologie 2009;32(6):356-358.

3. Tsilimparis N, Menenakos C, Rogalla P, Braumann C, Hartmann J.
Malignant melanoma metastasis as a cause of small bowel perforation.
Onkologie 2009;32(6):356-358.

4. Capizzi PJ, Donohue JH. Metastatic melanoma of the gastrointestinal
tract: a review of the literature. Compr Ther 1994;20:20-23.

4. Capizzi PJ, Donohue JH. Metastatic melanoma of the gastrointestinal
tract: a review of the literature. Compr Ther 1994;20:20-23.

5. Serin G, Doğanavşargil B, Calişkan C, Akalin T, Sezak M,
Tunçyürek M. Colonic malignant melanoma, primary or
metastatic? Case report. Turk J Gastroenterol 2010;21(1):45-49.

5. Serin G, Doğanavşargil B, Calişkan C, Akalin T, Sezak M,
Tunçyürek M. Colonic malignant melanoma, primary or
metastatic? Case report. Turk J Gastroenterol 2010;21(1):45-49.

6. Marks JA, Rao AS, Loren D, Witkiewicz A, Mastrangelo MJ, Berger AC.
Malignant melanoma presenting as obstructive jaundice secondary to
metastasis to the ampulla of Vater. J Pancreas Online
2010;11(2):173-175.

6. Marks JA, Rao AS, Loren D, Witkiewicz A, Mastrangelo MJ, Berger AC.
Malignant melanoma presenting as obstructive jaundice secondary to
metastasis to the ampulla of Vater. J Pancreas Online
2010;11(2):173-175.




    
        
            

        

    

    
        

    

    
        

    

    
        
            

        

    

    
        
        1a

        

        
            
        

        1b
        				

    

    
        
            Fig. 1. Axial post-contrast CT, venous phase at the level of the
            pelvis, showing a large mass with central ulceration as well as
            contrast collection (1a) and an air fluid level (1b).2b

        

        
            
                

            

        

        
            
        

        
            2a

        

    

    
        
        2b

        Fig. 2. Axial (2a) and coronal (2b) post-contrast CT, venous phase,
        showing communication between contrast-containing mass and terminal
        ileum.

    




    
        
        

        
            Fig.
            3. Axial post-contrast CT scan, venous phase at the level of the
            kidneys, showing large para-pancreatic lymph nodes with central low
            density.