Unexpected maspin immunoreactivity in Merkel cell carcinoma

Abstract

Merkel cell carcinoma (MCC) is a rare but aggressive cutaneous neuroendocrine tumor, which multifactorial etiopathogenesis seems to be related to ultraviolet radiation, Merkel cell polyomavirus (MCV), and immunosuppression. In this paper, we present three cases of diagnosed MCC in apparently healthy Caucasians, two of them located in a sun-exposed area. They represented 0.25 % of all cutaneous malignant tumors diagnosed in our department. In the first case, MCC was diagnosed in the frontal region of a 67-year-old male, the second case was located in the right thigh of a 55-year-old female, whereas the third case involved the upper trunk of a 62-year-old female. All of these cases were diagnosed in the pT1 stage, having a diameter smaller than 2 cm, but the invasion depth involved the hypodermis. Microscopically, they consisted of small cells with round-oval nuclei having finely dispersed chromatin and well-defined nucleoli. Immunohistochemically, the tumor cells displayed positivity for keratin 20 and neuroendocrine markers, being negative for keratin 7 and S100 protein. Maspin immunoreactivity was seen in cases 1 and 3. Not one of the cases expressed DOG-1 or even TTF-1. Furthermore, this is the first report in literature about maspin positivity in MCC that might be related to sun exposure.

Partial Gastric Resection for Symptomatic Anemia following Diagnosis of Merkel Cell Carcinoma (MCC) of the Skin with Gastric Metastasis

“… 18 Immunohistochemical staining is necessary to demonstrate positivity for broad spectrum keratins (AE1/3), neuroendocrine markers (chromogranin, synaptophysin, neuron specific enolase, CD56), and CK20 positivity in a classic dot-like paranuclear pattern. 18 , 19 Available literature regarding MCC tumor cells immunoprofiles notes the use of maspin as a possible marker to assist the diagnosis of MCC, particularly in relation to sun exposure. 19 Though this stain was not readily available at our institution, its positivity appears to be suggestive of MCC and could be used as an additional marker when available.…”

“… 18 , 19 Available literature regarding MCC tumor cells immunoprofiles notes the use of maspin as a possible marker to assist the diagnosis of MCC, particularly in relation to sun exposure. 19 Though this stain was not readily available at our institution, its positivity appears to be suggestive of MCC and could be used as an additional marker when available. Negative staining with cd57, pax5, tdt, CK7, ttf-1, s-100, and LCA help rule out metastasis form other sites (small cell lung carcinoma), lymphoma, and melanoma.…”

“…Negative staining with cd57, pax5, tdt, CK7, ttf-1, s-100, and LCA help rule out metastasis form other sites (small cell lung carcinoma), lymphoma, and melanoma. 18 - 20 …”

PKCθ utility in diagnosing c-KIT/DOG-1 double negative gastrointestinal stromal tumors

“…Its expression is directly correlated with c-KIT positivity [ 14 ]; all of the DOG-1 positive cases expressed c-KIT in our material but not all of the c-KIT positive GISTs were also positive for DOG-1. Usually, DOG-1 does not mark other tumors, such as leiomyomas/leiomyosarcomas, melanomas, schwannomas, malignant peripheral nerve sheath tumors, inflammatory fibroid polyps, small cell carcinomas, Merkel cell carcinomas or seminomas [ 7 , 15 , 24 ]. Uncommonly, DOG-1 sporadic positivity was reported for renal tubes, eccrine glands and hair follicles.…”

Subcellular Expression of Maspin in Colorectal Cancer: Friend or Foe

“…No maspin nuclear positivity was proved for other histological subtypes such: the MSS neuroendocrine tumors (NET), neuroendocrine carcinomas (NEC), mixed adenoneuroendocrine carcinomas (MANEC) or primary choriocarcinoma of the gastrointestinal tract [41][42][43]. Other neuroendocrine tumors such Merkel cell carcinoma developed in sun-exposed areas or pancreatic mucinous cystic neoplasms with neuroendocrine differentiation proved to show infrequent positivity for maspin [44,45].…”