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More than skin deep?

BMJ 2010; 340 doi: https://doi.org/10.1136/bmj.c932 (Published 04 March 2010) Cite this as: BMJ 2010;340:c932

This article has a correction. Please see:

  1. Mark J Austin, specialist registrar in gastroenterology
  1. 1Medway Maritime Hospital, Gillingham, Kent ME5 2RU
  1. Correspondence to: drmarkaustin{at}aol.com

    A 46 year old man was admitted with a 6 week history of nausea, vomiting, and night sweats, and a weight loss of 2 stone (12.7 kg). His medical history included excision of a malignant melanoma (Breslow’s thickness 1.6 mm) from the left side of his neck 12 months earlier. There was no evidence of local recurrence, or lymphatic or metastatic spread, 6 months after resection. The patient did not smoke.

    Clinical examination was unremarkable. Initial investigations demonstrated mild leucocytosis, neutrophilia, and thrombocytosis. Contrast enhanced computed tomography of the abdomen (fig 1)and barium enhanced radiography of the small bowel (small bowel follow through; fig 2) were performed.

    Figure1

    Fig 1 Computed tomography scan of the patient’s abdomen

    Figure2

    Fig 2 Radiograph of the patient’s small bowel

    Questions

    • 1 What are the different types of malignant melanoma?

    • 2 What does Breslow’s thickness describe?

    • 3 What abnormalities are demonstrated on the computed tomography and radiograph images?

    • 4 What would be the investigation of choice to enable histological evaluation?

    • 5 What is the likely diagnosis?

    Answers

    1 What are the different types of malignant melanoma?

    Short answer

    The different types of melanoma are superficial spreading melanoma, lentigo maligna, acral lentiginous melanoma, and nodular melanoma.

    Long answer

    Melanomas fall into four basic categories. Superficial spreading melanoma is by far the most common type, accounting for about 70% of all cases of melanoma. This type of melanoma is seen most often in young people. It has the appearance of an irregular, flat, or slightly raised discoloured pigmented lesion, although the colour can vary between tan, brown, black, red, blue, and white. This type of melanoma can develop in a previously benign mole anywhere on the body, most likely on the trunk in men and the legs in women.

    Lentigo maligna usually appears as a flat or mildly elevated mottled tan, brown, or dark brown discoloured plaque. This type of in situ melanoma is found most often in the elderly on sun exposed skin on the face, ears, arms, and upper trunk. When this type of cancer becomes invasive, it is referred to as lentigo maligna melanoma.

    Acral lentiginous melanoma also spreads superficially before penetrating more deeply. It is quite different from the other types of melanoma, though, because it usually appears as a black or brown discoloration under the nails or on the soles of the feet or palms of the hands. It is the most common type of melanoma in Africans, African Americans, and Asians, and the least common among Caucasians.

    Nodular melanoma is usually invasive at the time it is first diagnosed. In most cases the lesion is black, but occasionally it is blue, grey, white, brown, tan, red, or skin tone in colour. The most frequent sites are the trunk, legs, and arms of elderly people and the scalp in men. Nodular melanoma is the most aggressive of the melanomas and is diagnosed in 10-15% of cases of melanoma.

    2 What does Breslow’s thickness describe?

    Short answer

    Breslow’s thickness measures in millimetres the distance between the upper layer, or granulous layer, of the epidermis and the deepest point of the tumour’s penetration, allowing staging of malignant melanomas. The thinner the Breslow’s thickness, the better the chance of a cure.

    Long answer

    The melanoma staging system, initially developed in 1983 by the American Joint Committee on Cancer, divides melanoma into four stages incorporating tumour thickness, anatomic level of invasion for stages I and II, involvement of regional lymph nodes for stage III, and distant skin, subcutaneous, nodal, visceral, skeletal, or neurological metastasis for stage IV. The seventh edition of the American Joint Committee on Cancer (AJCC) staging is shown in (table ).1

    Tumour staging (7th Edition AJCC Staging System)1

    View this table:

    The most important factors in the staging of melanomas are the thickness of the tumour, known as Breslow’s thickness, and the presence of microscopic ulceration, indicating that the epidermis covering the tumour is not intact. Breslow’s thickness measures in millimetres the distance between the upper layer, or granulous layer, of the epidermis and the deepest point of the tumour’s penetration. It cannot be used to assess in situ melanoma.

    Breslow’s thickness

    • In situ melanoma is confined to the epidermis

    • Thin tumours are less than 1.0 mm in thickness

    • Intermediate tumours are 1.01-2.0 mm

    • Thick tumours are 2.01-4.0 mm

    • Very thick melanomas are 4.01 mm or more.

    One of the most important indicators of the severity of a melanoma is whether it has spread. The initial spread is most likely to be into the lymph node closest to the primary tumour—the sentinel node. The possibility of metastasis should be considered in all tumours more than 1.0 mm in thickness or when a thinner tumour shows evidence of ulceration.

    3 What abnormalities are demonstrated on the computed tomography and radiograph images?

    Short answer

    The computed tomography and radiograph images show multiple polypoid filling defects in the proximal jejunum.

    Long answer

    The contrast enhanced computed tomography scan (fig 3) and barium enhanced radiograph image of the small bowel (small bowel follow through; fig 4) demonstrate multiple polypoid luminal filling defects in the proximal small bowel. The computed tomography scan also shows widespread mesenteric lymphadenopathy, but no liver metastases.

    Figure3

    Fig 3 Computed tomography scan of the patient’s abdomen. Arrows indicate filling defects within jejunum

    Figure4

    Fig 4 Radiograph of the patient’s small bowel. Arrows indicate filling defects within small bowel loops

    Clinical examination with endoscopic and radiological imaging is essential for diagnosis of small bowel metastatic melanoma. Contrast enhanced computed tomography is useful for diagnosis and staging of metastatic small bowel melanoma, given that this technique has 60-70% sensitivity for detection of intestinal melanoma. Computed tomography enteroclysis is the preferred imaging method for patients with symptoms of intermittent small bowel obstruction, but is contraindicated for patients with complete bowel obstruction.

    4 What would be the investigation of choice to enable histological evaluation?

    Short answer

    The investigation of choice to facilitate histological evaluation is small bowel enteroscopy and biopsy.

    Long answer

    Small bowel enteroscopy and biopsy of polyps in the proximal jejunum would be required to get samples for histological evaluation (fig 5). Endoscopic examination of the small bowel is a recognised procedure for the diagnosis of gastrointestinal tumours. The jejunum and ileum can be visualised using straightforward push enteroscopy or via single or double balloon enteroscopy.

    Figure5

    Fig 5 Enteroscopy images of the proximal jejunum. Arrows indicate multiple polypoid lesions within the small bowel lumen

    Alternatively, capsule endoscopy can be used to investigate segments of the intestine, although an endoscopic procedure would still be required to obtain histology samples. Patients presenting with bowel obstruction who undergo laparotomy will not require endoscopic evaluation.

    5 What is the likely diagnosis?

    Short answer

    The most likely diagnosis is superficial spreading metastatic malignant melanoma.

    Long answer

    This patient has superficial spreading metastatic malignant melanoma. Melanoma of the small intestine can be metastatic in origin in patients with a history of a skin, anal, or ocular melanoma. Metastatic intestinal melanoma is very common, with a prevalence of 35% to 70%.2 3 4 Small bowel involvement is seen in 91% of patients who have surgical exploration (laparotomy) for melanoma metastases to the gastrointestinal tract. Although around 60% of patients who die from melanoma have gastrointestinal metastases, only 1.5-4.4% of metastases to the gastrointestinal tract are detected before death.4 5 6 7

    Superficial spreading melanoma is the most common form of melanoma (70-80%) and is the type most likely to metastasise to the small intestine.8 Unlike primary intestinal melanoma, superficial spreading melanoma is equally likely to metastasise to the ileum as to the jejunum.9 There are four different types of superficial spreading melanoma, although the categories are not always distinct: cavitary; infiltrating; exoenteric; and polypoid.

    Metastatic melanoma of the small bowel typically forms multiple polypoid masses in the submucosal region.8 9 Polyposis is defined as the presence of more than ten polypoid lesions involving the jejunum and ileum. Metastatic intestinal melanoma less commonly presents as a solitary mass. 9 10 The clinical picture of small bowel melanoma is similar to the clinical presentation of other tumours involving the small intestine. Thus, patients with a history of cutaneous melanoma who have intermittent abdominal pain or anaemia should be investigated for possible metastatic disease.

    In many patients with metastatic intestinal melanoma, the disease is undetectable in early stages and diagnosis is made only when complications occur or after death. In more than 50% of patients with gastrointestinal melanoma, however, extraintestinal metastases are detected at the time of diagnosis.11 Although intestinal metastases typically develop 3-6 years after excision of the primary cutaneous melanoma, they are sometimes present at initial diagnosis or just 6 months after detection of primary cutaneous lesions.9 11 12

    Treatment of metastatic disease can include chemotherapy (dacarbazine), immunotherapy, or biochemotherapy.10 Preoperative and postoperative chemotherapy regimens have been tried.13 Systemic chemotherapy regimens have no benefit on overall survival in patients with intestinal metastatic melanoma. Systemic chemotherapy might be useful as a palliative treatment, however, although the role of adjuvant therapies is unclear.3 14 Currently, the prognosis for patients with metastatic melanoma is poor, with an overall median survival of 6-9 months and a 5 year survival rate of less than 10%, irrespective of the site of metastatic deposit.15

    Patient outcome

    This case was discussed at the gastroenterology multidisciplinary meeting and the dermato-oncology meeting. It was felt that the patient would be a candidate for palliative care. He was discharged home 1 month from his presentation. Unfortunately, he was readmitted 1 week later with subacute small bowel obstruction, which was treated conservatively. He was placed on the Liverpool care pathway and died the following day.

    Notes

    Cite this as: BMJ 2010;340:c932

    Footnotes

    • Competing interests: The author has completed the Unified Competing Interest form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declares (1) No financial support for the submitted work from anyone other than his employer; (2) No financial relationships with commercial entities that might have an interest in the submitted work; (3) No spouses, partners, or children with relationships with commercial entities that might have an interest in the submitted work; (4) No non-financial interests that may be relevant to the submitted work.

    • Patient consent obtained.

    • Provenance and peer review: Not commissioned; externally peer reviewed.

    References

    View Abstract

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