’Carcinoma en cuirasse' in the neck: extremely unusual initial presentation of gastric cancer

Abstract

Cutaneous metastasis from visceral malignancy is a relatively rare phenomenon. It is even rarer to have cutaneous lesions as the first mode of clinical presentation in such malignancies. The lesions are usually nodular, although they can have varied appearances. Common sites of primaries include breast, lung, colorectum, kidney, ovary, and headandneck. We report an unusual form of cutaneous metastasis in the neck, known as ‘carcinoma en cuirasse’, in an elderly man that subsequently led to the diagnosis of an occult gastric cancer. Our case highlights the importance of recognising cutaneous metastatic lesions early, as they may herald the diagnosis of an occult internal malignancy.

Background

Cutaneous metastases of visceral malignancies are relatively rare, constituting about 2% of all skin tumours.¹ A vast majority of these arise from breast and lung cancers, while less frequently, these arise from colorectal, renal, ovarian, and head and neck cancers. Skin metastasis from gastric adenocarcinoma is particularly uncommon, with a reported incidence of 0.8%.² The lesions are usually nodular, often located in the abdominal wall, including the well-known Sister Mary Joseph nodules in the umbilicus.³ Rarely, they can present with non-metastatic, paraneoplastic cutaneous manifestations, such as dermatomyositis, acanthosis nigricans, eruptive seborrheic keratosis (sign of Leser-Trélat), Trousseau’s syndrome and vasculitis.⁴ It is extremely rare for gastric carcinoma to present solely with a peculiar form of cutaneous metastasis, known as ‘carcinoma en cuirasse’, at a distant site. We describe such a case in an elderly man, who presented initially with a cuirasse lesion in the neck and was later diagnosed to have a gastric adenocarcinoma.

Case presentation

A 60-year-old man presented to our outpatient department with a 10-month history of progressive thickening and hyperpigmentation of skin over the anterior neck. The lesion was initially small and gradually progressed to involve the entire anterior neck. There was no history of associated pain, itching, scaling or oozing in the lesion. The patient did not report any significant weight loss, fever or symptoms pertaining to any other system. On examination, an extensively indurated, well-demarcated, non-tender, leathery plaque (10×8 cm) was seen in the anterior and lateral aspects of the neck, extending from just below the chin to the suprasternal notch (figure 1). There was no visible desquamation, crusting, erythema, vesicles or papulonodular lesions. No other skin lesions were seen elsewhere in the body. Results of clinical examination of the breasts were normal. Significant lymphadenopathy was absent. The result of the oral cavity and nasal examinations was unremarkable. Flexible laryngoscopy did not reveal any laryngeal lesion.

Figure 1.

Clinical picture showing a thickened hyperpigmented skin plaque in the anterior neck—‘carcinoma en cuirasse’.

Investigations

All the routine haematological and biochemical investigations, including thyroid function test, and chest X-ray were normal. Autoimmune serology was negative. Fine needle aspiration was attempted twice but was inconclusive due to dilution with blood. Skin biopsy (figure 2) from the lesion showed a normal epidermis. There was diffuse infiltration of the dermis by atypical cells, arranged singly and in glandular pattern in a fibrous stroma. Signet ring cells containing intracellular mucin were noted occasionally. On immunohistochemistry, these cells were positive for CK7 but negative for CK20, TTF-1, CEA, GCDFP15, oestrogen receptor, progesterone receptor and prostate-specific antigen. A diagnosis of metastatic adenocarcinoma was suggested, with possible primary sites being upper gastrointestinal (GI) tract and lung. An upper GI endoscopy revealed an ulceroproliferative growth in the gastric antrum that proved to be an adenocarcinoma with abundant signet ring cells on histological examination (figure 3).

Figure 2.

(A) Photomicrograph showing diffuse infiltration of dermis by an adenocarcinoma (H&E, ×40). (B) A higher magnification of tumour cells demonstrating the presence of intracytoplasmic mucin vacuoles (signet ring cells) (H&E, ×400). (C) Signet ring tumour cells highlighted by Alcian blue–periodic acid–Schiff stain (×400); tumour cells are immunonegative for oestrogen receptor, (D) progesterone receptor (E) and GCDFP15 (F) (IHC, x400). IHC, immunohistochemistry.

Figure 3.

(A) White light endoscopy image and (B) narrow band image of ulceroproliferative growth in the stomach. (C) Gastric biopsy demonstrating a poorly differentiated adenocarcinoma with numerous signet ring cells (H&E, ×400). (D) Intracytoplasmic mucin in signet ring cells highlighted by Alcian blue–periodic acid–Schiff stain (×400).

Differential diagnosis

A dermatological consultation was sought and the clinical differential diagnoses considered were

• Lichenified dermatitis.

• Scleroderma.

• Sarcoidosis.

• A malignant skin lesion.

Treatment, outcome and follow-up

The patient was advised to undergo a whole-body positron emission tomographic scan and was referred to the oncology department for further management. However, the patient deferred any treatment and died within 3 months of presentation.

Discussion

Visceral malignancies metastasising to skin is a relatively uncommon phenomenon in clinical practice, with an overall incidence ranging from 0.7% to 10.4%.^{1 3 5} Lung cancer is the most common source of cutaneous metastasis in men and breast cancer in women.³ Cutaneous metastasis usually occurs in terminal disseminated stage or as a sign of recurrence in established visceral malignancies. However, it may be the first presenting feature in less than 1% of patients with an occult internal malignancy.⁶

Cutaneous metastasis is seen in 0.8% to of gastric cancers and constitutes 6% of all cutaneous metastases.^{2 5} Clinically, the lesions are usually located in the anterior abdominal wall and are typically nodular with or without ulceration. Rarely, they can have unusual appearances like erysipeloid lesions,⁷ zosteriform lesions³ or as thick, indurated, fixed and extensively infiltrating plaques known as carcinoma en cuirasse, as in our case. Cuirasse is a French word derived from the Latin term ‘coriaceous’ (meaning ‘like leather’), used to describe the breastplate of ancient warriors. Since the first description of carcinoma en cuirasse by Velpeau in 1838, it has been widely recognised in breast cancer with chest being the the most common site. These peculiar lesions have occasionally been reported in prostatic, uterine, genital and lung cancers at various sites.^8–11 Harvey and Cochrane documented this pattern of cutaneous metastasis in gastric cancer for the first time, involving the chest wall, followed by few case reports mostly involving the anterior abdominal wall.^12–16 To the best of our knowledge, ours is the first case of gastric carcinoma presenting with isolated cuirasses’ pattern of metastasis at a distant site such as the neck in the English literature.

Histopathological examination is important to establish the diagnosis and can provide a clue to the possible primary site based on certain morphological and immunohistochemical features. Signet ring cells, though traditionally seen in adenocarcinomas arising from the stomach, colon, breast, prostate or lung, may be seen in many primary skin tumours.¹⁷ However, demonstration of intracytoplasmic mucin by histochemical stains (Alcian blue–periodic acid–Schiff stain or mucicarmine) favours a metastatic lesion over primary tumour arising in the skin. Immunohistochemical markers that are commonly used to determine the primary site include CK7 (positive in adenocarcinomas arising from upper aerodigestive tract), CK20 (colon), TTF-1 (lung and thyroid), prostate-specific antigen (prostate), Gross Cystic Disease Fluid Protein (GCDFP) and hormonal receptors (breast). Presence of signet ring cells with intracellular mucin and immunopositivity for CK7 suggested a gastric primary in our case, which was subsequently confirmed by endoscopic findings. An exceptionally rare possibility of metastatic lobular breast carcinoma mimicking a primary gastric tumour was ruled out by immunonegativity for oestrogen receptor, progesterone receptor and GCDFP.¹⁸

Cutaneous metastasis is associated with a poor prognosis, with an average survival time of less than a year.² Treatment for most of these patients is palliative, and although chemotherapy and radiotherapy are often used, they have a limited impact on survival in many cases.

In summary, cutaneous metastasis as a presenting feature of an undiagnosed visceral malignancy is very rare and can occur anywhere in the body, not necessarily in contiguity to primary site. Physicians and dermatologists should be aware of certain unusual patterns of cutaneous metastasis, carcinoma en cuirasse being one of them. Any unexplained skin lesion should therefore be evaluated carefully and promptly biopsied, as timely diagnosis of an internal malignancy significantly improves patient prognosis.

Learning points.

• Cutaneous metastases, though relatively rare, may be the first sign of an occult internal malignancy.

• Persistent, indurated, erythematous skin lesions, cutaneous nodules and plaques of undetermined cause need to be biopsied early to ensure diagnosis, to institute appropriate therapy and thereby to improve patient survival.

• The treatment for most patients with cutaneous metastasis is palliative.

• Our case highlights the need for clinicians to be aware of uncommon patterns of cutaneous metastases.