Anaemia due to gastric haemorrhage by a metastatic Merkel cell carcinoma

Merkel cell carcinoma (MCC) is an aggressive uncommon neuroendocrine tumour of the skin, probably originating from Merkel cells, and described by Toker in 1972 as Trabecular carcinoma [1]. Subsequently, electron-dense neurosecretory granules were demonstrated in the tumour cells and it was classified as definite neuroendocrine tumour. Merkel cell carcinoma is characterised by a high incidence of local recurrences, regional local metastases, distant metastasis, and high mortality rate [2]. Merkel cell carcinoma occurs predominantly in elderly white males (61% male vs. 39% female), with a mean age of 69 years at diagnosis [3]. Lately, reports on MCC have increased, probable due to the higher incidence of damaging sun exposure, the advancing age of the population, and the increasing numbers of immunocompromised individuals [3]. In fact, it has been described that MCC is strongly associated with a polyomavirus [4], which might explain why MCC appears more frequently in immunocompromised patients such as solid-organ transplant recipients and HIV/AIDS infected people, and is associated with other malignancies [5]. Taking all of the data together, MCC could sometimes appear as a metastatic tumour in many different organs such as liver, bone, lung, and brain [6]. In light of this we report herein a patient who developed anaemia due to gastric haemorrhage as the first sign of gastric metastasis by MCC, which has rarely been reported [7].
A 52-year-old man with a previous diagnosis of type 2 diabetes mellitus and mild retinopathy was referred to our hospital due to severe asthaenia and dizziness. Almost 2 years previously, a cutaneous surgical excision was performed removing a 2 cm well-delimitated solid nodule on his right thigh, diagnosed as a Merkel cell carcinoma after a battery of immunohistochemical tests (Figures 1 A, B). Moreover, ipsilateral inguinal lymphadenectomy was done revealing one infiltrated lymph node. The patient underwent local radiotherapy (5000 RADs) in combination with chemotherapy (carboplatin and etopoxide) with a very good clinical tolerance. So far, the patient has been asymptomatic.
The current physical examination of the patient pointed out a paleness of the skin and mucous membranes. An extensive workup was performed showing intense anaemia with haemoglobin level of 8.4 g/dl. Abdominal computed tomography (CT) highlighted a gastric wall thickening with associated regional lymphadenopathy. Subsequently, gastroscopy showed...


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