Large-cell neuroendocrine carcinoma of the skin, with lymphoid stroma

Large Cell Neuroendocrine Carcinoma of the Skin/Conjunctiva: A Series of 6 Cases including 1 Combined Case With Squamous Cell Carcinoma

ABSTRACT

This study sought to reveal the clinicopathologic characteristics of large cell neuroendocrine carcinoma (LCNEC) of the skin/conjunctiva. The retrieved patients included 3 men and 3 women with a median age of 85 (63-95) years. All lesions occurred on the face, including the ears, with a median tumor size of 11.5 (7-65) mm. Lymph node metastasis was observed in 5 (83%) of 6 cases, and distant metastasis was noted in 2 (33%). One patient (17%) who had a 13-mm-sized tumor died of the tumor 13 months after excision. All tumors were mainly located in the dermis, and one of them also exhibited intraepithelial spreading. The cytology resembled that of an LCNEC in other organs. No adnexal differentiation was observed. Five cases were of the pure type, but one had a component of squamous cell carcinoma. Immunoreactivities for CAM5.2, CK7, CK19, BerEP4, epithelial membrane antigen, neuron-specific enolase, synaptophysin, c-KIT, GATA3, and bcl-2 were frequently present, but CK20, neurofilament, Merkel cell polyomavirus large T antigen, mammaglobin, estrogen receptor, HER2, and TTF1 were completely negative in all cases. Mutant-pattern immunostaining of p53, PTEN, and Rb was frequently observed. The Ki67 rate exceeded 70% in all cases. LCNEC of the skin/conjunctiva is a morphologically-defined group of primary cutaneous/conjunctival neuroendocrine neoplasm, although it may be heterogeneous similar to other-site LCNEC or Merkel cell carcinoma. This study highlighted the predominant location for the face, high metastatic and lethal potential, possible combination with other tumor components, and frequent mutant-type immunoexpressions of p53, PTEN, and Rb in this tumor group.

Primary large cell neuroendocrine carcinoma of the skin: An under-recognized entity and a mimic of metastatic disease

Primary large cell neuroendocrine carcinomas of the skin are exceptionally rare and can be diagnosed only when a metastasis from another organ has been excluded. We report the case of a 62-year-old woman with a cutaneous papule on the mid-chest which generated a differential diagnosis of vascular lesion and basal cell carcinoma. Following excision, microscopic evaluation revealed a dermal large cell undifferentiated carcinoma, with a brisk mitotic rate and focal geographic necrosis. Mucin production was absent. On immunohistochemistry, the lesion expressed CK7, AE1AE3, CK8/18, chromogranin, synaptophysin, CD56, calcitonin (patchy) and TTF-1 (minimal focal). Stains for neurofilament, CK20, CK5/6, p40, p63, SOX10, MART-1, EMA, CEA, ER/PR, GATA3, GCDFP, mammoglobin, PAX-8, CDX2, napsin, ERG and MCPyV proved negative. The histopathological diagnosis was of a large cell neuroendocrine carcinoma, probably metastatic. The patient underwent comprehensive clinical, laboratory and radiographic investigations and no underlying primary carcinoma was detected. During a 20-month follow-up period with an oncologist, the patient remains well and free of any apparent carcinoma. This suggests a primary large cell neuroendocrine carcinoma of skin. To date, 3 such cases have been reported in Japanese patients. This is the first in a Caucasian resident of North America.

Cutaneous neuroendocrine carcinoma of the external auditory canal: a case report and review of the literature

Cutaneous neuroendocrine carcinoma (cNEC) is rarely seen in the external ear. In this paper, we newly describe a patient with cNEC in his right external auditory canal, followed by a further discussion on the clinical features, diagnosis, and treatments of cNEC of the external ear. A review of the literature showed that cNEC of the external auditory canal generally presents as asymptomatic and that pathology yields the most confirmative diagnosis. A wide resection with adjuvant radiotherapy and chemotherapy is recommended. The overall prognosis of this condition is poor.

CK20 Positive Large-cell Neuroendocrine Carcinoma Presenting with Skin Metastases

We present a case of cytokeratin (CK) 20-positive large cell neuroendocrine carcinoma (LCNEC) presenting with multiple skin metastases as the primary manifestation. The patient was a 55-year-old man who presented with a one- month history of subcutaneous skin colored nodules of various sizes on his trunk. Pathologic examination of the skin revealed a nested and solid proliferation of large undifferentiated cells with vesicular nuclei and prominent nucleoli. Tumor cells were found to be immunohistochemically positive for CK 20, chromogranin A, synaptophysin, and CD56. Based on these features, the tumor was diagnosed as a large cell neuroendocrine carcinoma with multiple skin metastases. Computed tomographic (CT) imaging found metastatic foci in the liver, pleura, bone, and lymph nodes. We were unable to identify the primary site of origin. To the best of our knowledge, this is the first case of a large cell neuroendocrine carcinoma with a primary manifestation of multiple skin metastases.

Merkel cell carcinoma with lymphoepithelioma-like pattern: a case report of an exceedingly rare variant of merkel cell carcinoma with lymph node metastases at presentation

Merkel cell carcinoma (MCC) or primary neuroendocrine carcinoma of the skin is a rare neoplasm with aggressive behavior. Primary lymphoepithelioma-like (LEL) carcinoma of the skin is a recently described exceptional tumor, with a relatively good prognosis, and is characterized by a neoplastic epithelial component associated with a dense lymphoid stroma. Rarely, MCC shows a marked lymphocytic host response or can even mimic a LEL carcinoma. We report a new case of MCC mimicking an LEL carcinoma in a 72-year-old male; the diagnosis of MCC was made on the basis of the morphology and immunohistochemical findings. We present through this case an exceptional pattern of MCC which can be misleading, and we insist on differential diagnoses.