Unusual Presentation of a Cutaneous Malignancy: Giant Merkel Cell Carcinoma with Intra-abdominal Metastasis.
Merkel cell carcinoma (MCC) is a rare and aggressive cutaneous malignancy with uncertain histogenesis. It is believed to be a neuroendocrine tumor originated from the Merkel cells of the epidermis and associated with high rates of metastasis. White, elderly, Caucasian individuals are mostly affected with an estimated annual incidence of 0.6/100,000. Although it can potentially occur at any site of the body, it is mostly seen in the sun-exposed areas of head and neck region and the extremities. Here, we present an unusual presentation of giant MCC of the skin with concomitant intra-abdominal metastasis to the pancreas.
A 53-year-old man admitted to the outpatient dermatology clinic with a giant mass in the gluteal region. A detailed history revealed that the lesion started as a millimetric asymptomatic papule 9 months ago which progressed rapidly into a giant ulcerated mass. Initially, the patient had admitted to elsewhere and punch biopsy of the papule was evaluated there as superficial perivascular dermatitis and the patient was discharged following antibiotherapy. Following admission to our institution, dermatologic evaluation revealed a centrally necrotic, foul-smelling, and hemorrhagic giant mass measuring 20 cm x 15 cm x 7 cm at the left gluteal region [Figure 1]. The patient was referred to plastic surgery clinic and the incisional biopsy of the mass revealed primary poorly differentiated neuroendocrine tumor of the cutaneous origin and confirmed the diagnosis of MCC.
Clinically, the patient complained of abdominal discomfort and weight loss of 15 kg over the past 4 months. Intra-abdominal computerized tomographic examination demonstrated a heterogenous-appearing giant mass of the right upper quadrant invading the superior mesenteric artery and leading to obstruction of common biliary duct and a second mass (6 cm x 6 cm) located at the inferior pole of pancreas extending toward the duodenum [Figure 2].
As the gluteal mass was prone to trauma and leading to massive hemorrhage, excision of the gluteal mass with 2 cm of tumor-free margin including the underlying gluteal muscles was performed. Intraoperatively, there was significant suspicion of invasion of the underlying, and to achieve tumor-free margins, both the underlying fascia and associated gluteal muscles were partially removed. V-Y advancement flap based on the perforators of the inferior gluteal and profunda femoris artery was elevated to cover the resulting 22 cm x 17 cm defect [Figure 3].
On microscopical examination of the excision material, the neoplasm was highly cellular and infiltrated fat and muscle. Neoplastic cells were dyscohesive, having round-oval nuclei with finely granular to vesicular chromatin. Mitotic figures and apoptotic figures were abundant. Immunohistochemically neoplastic cells displayed CK20, CD138, CD56, and chromogranin positivity; weak pancytokeratin positivity was noted. Perinuclear dot-like CK20 positivity would be diagnostic for MCC, but a close look on CK20 staining revealed neoplastic cells that had diffuse cytoplasmic staining as well as neoplastic cells with perinuclear dot-like staining [Figure 4]. After a discussion on the clinical and radiological features of the patient, the mass in the pancreas was diagnosed as metastasis of the MCC of the skin. In respect to the metastatic staging of the disease, the intra-abdominal mass was evaluated as unresectable and palliative relief was planned by biliary drainage.
Even though postoperative follow-up was uneventful and no major complications were observed, pain during mobilization was obvious for the 1st postoperative month. Although the patient was referred to medical oncology for further therapeutic management, he could only survive for 11 months from his initial diagnosis.
MCC is a rare neuroendocrine malignancy with aggressive behavior. The most common sites of involvement are the head and neck (50%) and the extremities (40%). MCC occurs mostly in the elderly population with a mean age of diagnosis of 70 years. Although the exact etiology remains unclear, there is high association with chronic sun exposure and immunosuppression. The majority of patients were diagnosed with tumor size <2 cm and at the stage of localized disease. Due to the aggressive nature of the malignancy, it has a high tendency for local recurrence and distant metastasis.
MCC was first described by Toker in 1972 as a skin malignancy originated from the sweat gland and has been named as "trabecular cell carcinoma of the skin." Later by introduction of electron microscopy, dense secretory granules of Merkel cells were visualized in the tumor cells unclearing the origin of the pathology. Even though there is no doubt about the involvement of Merkel cells, exact histogenesis of the pathology is still uncertain. Merkel cells are located in the epidermis and contain cytokeratin only, whereas the malignant counterpart MCC contains both cytokeratin and neurofilament proteins and located in the dermis of skin. One-, 2- and 3-year survival in MCC is expected as 88%, 72%, and 55%, respectively. No 5-year survival has been reported so far.
There are a variety of histological subtypes including trabecular, intermediate, and small cell variant, and histopathologically, it is relatively challenging to distinguish MCC from other poorly differentiated small cell tumors. It can be confused with lymphomatous deposits, small cell melanoma, and metastatic small cell carcinoma, primarily of bronchial origin. Immunohistochemical studies can reveal the exact nature and the origin of the tumor in a vast majority of cases, taken into account together with clinical findings.
In the literature, various distant metastasis related to MCC are reported.[1,2,4,7,8] To the best of our knowledge, this case is the first case reported in the literature with giant mass of MCC located in the gluteal region and one of the 10 cases of pancreas metastasis of MCC was previously reported. Moreover, not many cases were reported with such aggressive behavior with rapid growth of the primary tumor and appearance of giant conglomerated intra-abdominal metastatic mass in a quite short interval. When the mean age of diagnosis of MCC is taken into consideration, our case is diagnosed in relatively young age.
Currently, there is no agreement on management of MCC. Conventional approach consists of wide local excision with 2-3 cm tumor-free margins and application of adjuvant radiotherapy for microscopic remnants if angiolymphatic involvement is observed. When the aggressive biological behavior of the malignancy is taken into consideration, the presence of unfavorable prognostic factors may also warrant elective lymph node dissection. For unresectable cases, systemic chemotherapy and radiotherapy are the available options.[1,4,9]
Posterior thigh flap (PTF), initially described by Shintomi and Ohura in 1983, is a fasciocutaneous flap supplied by the vascular network of descending branch of inferior gluteal, medial circumflex, and profunda femoris arteries. Later on, various modifications have been described, one of them being its elevation based on perforators to maximize flap mobilization. In this case of presentation for reconstruction of the gluteal defect following wide local excision of the MCC with 2 cm of tumor-free margins, a fasciocutaneous flap in a V-Y advancement fashion based on the perforators of the inferior gluteal and profunda femoris artery was planned. Our opinion is that PTF is an excellent and durable flap choice for reconstruction of such large gluteal defects as it does not lead to significant donor site morbidity.
MCC is a cutaneous malignancy with aggressive biological behavior and high rates of metastasis. We presented a case of rapidly progressing giant gluteal MCC concomitant with multiple intra-abdominal metastatic masses. We would like to emphasize that MCC has the potential to spread to unusual organs in short intervals and prompt evaluation and proper management is essential for optimal survival of these patients.
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The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that names and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.
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Mert Calis, Omer Ekin, Pelin Memis (1), Gunes Guner (2), Derya Karakoc (3), Gonca Elcin (1), Ali Emre Aksu
Departments of Plastic and Reconstructive and Aesthetic Surgery, (1) Dermatology and Venereology, (2) Pathology and (3) Surgery, Faculty of Medicine, Hacettepe University, Ankara, Turkey
Address for correspondence: Dr. Mert Calis, Department of Plastic, Reconstructive and Aesthetic Surgery, Faculty of Medicine, Hacettepe University, Ankara, Turkey.
How to cite this article: Calis M, Ekin O, Memis P, Guner G, Karakoc D, Elcin G, et al. Unusual presentation of a cutaneous malignancy: Giant merkel cell carcinoma with intra-abdominal metastasis. Turk J Plast Surg 2018;26:131-4.
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|Title Annotation:||Case Report|
|Author:||Calis, Mert; Ekin, Omer; Memis, Pelin; Guner, Gunes; Karakoc, Derya; Elcin, Gonca; Aksu, Ali Emre|
|Publication:||Turkish Journal of Plastic Surgery|
|Article Type:||Case study|
|Date:||Jul 1, 2018|
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