Atypical carcinoid metastasis to the skin

Skin and Subcutaneous Tissue Metastases of the Pulmonary Carcinoid Tumor on 68 Ga-DOTATATE PET/CT

ABSTRACT

Pulmonary carcinoid tumors are a very rare type of neuroendocrine tumor, accounting for only 1% to 2% of all primary lung cancers. Pulmonary carcinoids most commonly metastasize to the mediastinal lymph nodes, liver, and bones. Metastasis of pulmonary carcinoids to the skin and subcutaneous tissue is extremely rare and has been reported in only a small number of cases. We presented 68 Ga-DOTATATE PET/CT findings of an exceptional case of a pulmonary carcinoid tumor with extensive skin, subcutaneous, thyroid, and intramuscular metastases.

Alopecia neoplastica as a sign of visceral malignancies: a systematic review

Alopecia neoplastica (AN) from visceral tumours is a rare form of cutaneous metastasis in which internal malignancies spread to the scalp. The diagnosis of AN may be very challenging, especially when its onset precedes the diagnosis of the primary tumour. We aimed to improve the knowledge on AN, highlighting that in case of scarring localized alopecia, a differential diagnosis with metastasis should always be considered. We performed a systematic review to describe the main demographic and clinical features associated with AN from visceral malignancies; a survival analysis was also performed. In 118 reports, accounting for 123 patients, we found that women were more affected by AN than men (53.7% vs. 46.3%). The most frequent site of the primary tumour was the gastrointestinal tract (24.4%), followed by breast (17.9%), kidney (8.1%), lung (7.3%), thyroid (7.3%), uterus (6.5%), central nervous system (6.5%), liver (3.3%) and other anatomic areas for 18.7% of cases. Furthermore, in more than half of the cases (66.1%), AN lesions were single and were mainly diagnosed after the primary visceral tumour (71.5%). Finally, survival analysis highlighted a lower progression-free survival in men; while, no significant differences in overall survival were reported among genders. In conclusion, metastatic skin disease should always be taken into consideration when dealing with patients with localized scarring alopecia.

Well-differentiated neuroendocrine tumors in skin: Terminology and diagnostic utility of cytokeratin 5/6 and p63

BACKGROUND

Well-differentiated neuroendocrine tumors (WDNETs) in skin include metastases from visceral primary sites and very uncommonly, primary cutaneous carcinoid tumors. Cutaneous WDNET may present a diagnostic challenge and in particular can be mistaken for a benign skin adnexal tumor. In contrast to cutaneous adnexal tumors, metastatic adenocarcinomas to the skin are cytokeratin 5/6 (CK5/6) and p63 negative in the majority of cases. It is unclear if failure to stain with CK5/6 and p63 would be helpful in differentiating WDNETs from cutaneous adnexal neoplasms.

METHODS

We reviewed 10 cases of cutaneous WDNETs (8 cases of metastatic disease and 2 presumed primary carcinoid tumors of the skin) and performed immunohistochemical stains for CK5/6 and p63 on all cases.

RESULTS

All 10 cases were negative with both CK5/6 and p63.

CONCLUSION

Negative staining for CK5/6 and p63 can be helpful to distinguish WDNETs from cutaneous adnexal neoplasms. It is important to consider WDNETs in the differential diagnosis of cutaneous adnexal neoplasms as low-grade tumors may be the first sign of aggressive metastatic disease.

Cutaneous Metastasis of Neuroendocrine Carcinoma with Unknown Primary Site: Case Report and Review of the Literature

We report a new case of neuroendocrine carcinoma for which it was not possible to find the primary site until now. The recent medical literature about skin metastasis of neuroendocrine carcinoma (neuroendocrine tumor) is discussed.

Primary Carcinoid Tumor of the Skin

Primary carcinoid tumor of the skin (PCTS) is an uncommon indolent neoplasm, with 10 cases described in the literature. The tumors affect patients in the sixth to ninth decades of life (mean = 66.3 years) with an equal gender distribution and predilection for the head and trunk. They present as slowly enlarging nodules of variable duration, ranging from 1 to 60 years (mean = 11.4 years). PCTS is characterized by architectural, cytomorphologic, ultrastructural, and immunohistochemical features typical of a low-grade neoplasm with neuroendocrine differentiation. PCTS typically follows a benign clinical course and therefore has to be distinguished from cutaneous metastases of visceral carcinoid tumors, which herald dissemination of malignancy and poor prognosis. While the distinction from other histologically similar entities can be achieved by histopathological examination, PCTS can be distinguished from a visceral metastasis only by a judicious clinicopathologic correlation. Herein we describe the clinical presentation, histological appearance, and management of these tumors.

Cutaneous metastases as an initial manifestation of visceral well-differentiated neuroendocrine tumor: a report of four cases and a review of literature

Well-differentiated neuroendocrine tumors metastasize to the skin uncommonly, and only 35 cases are reported in the literature. In only five of these patients, cutaneous metastases were the presenting symptom of malignancy; herein, we report four such cases. Two patients were female and two male, aged 50-74 years (mean: 64.5 years), each with a solitary painless, slowly enlarging, non-ulcerated cutaneous nodule of 3-12 months duration (mean: 9 months). The lesions were on the scalp (n = 3) and trunk (n = 1), and ranged in greatest dimension from 0.5 to 2.5 cm. The distinction from other microscopically similar entities, and the interpretation of origination from gastrointestinal, pancreatic or respiratory system primaries, was made clinically, or was based on the morphological features and the immunohistochemical profile. One patient died of the disease progression after 36 months whereas two patients are alive with significant disease progression after 24 and 60 months. Metastatic neuroendocrine tumor should be considered in the differential diagnosis of cutaneous tumors with neuroendocrine morphology even in patients with no known history of visceral malignancy.

Nasal tumor with widespread cutaneous metastases in a Golden Retriever

An intact, 8-year-old, male Golden Retriever dog was presented for evaluation of a nasal mass and approximately 30 firm, raised, variably ulcerated dermal and subcutaneous masses. Histopathology of both nasal and multiple skin masses revealed multiple nonencapsulated, infiltrative masses comprising clusters, anastomosing trabeculae, and packets of neoplastic, round to ovoid, hyperchromatic cells with marked nuclear molding. Surrounding the neoplastic cells was a marked stromal response in which many of the spindle-shaped cells expressed muscle-specific actin and had ultrastructural features consistent with myofibroblasts. A literature search indicates that this is the first report in a peer-reviewed journal of cutaneous metastasis of a nasal neuroendocrine tumor in any domestic animal species.