RESUMO

BACKGROUND: Merkel cell carcinoma (MCC) is an aggressive cutaneous neuroendocrine carcinoma that affects elderly patients and typically arises in sun-exposed skin. The disease is very rare and only few cases present with no apparent skin lesion. In the retroperitoneum there are only two cases reported in the literature. CASE PRESENTATION: We report a case of a 54-year-old Mexican male with MCC, which presented as a large retroperitoneal mass. Pathological and immunohistochemical analysis of the transabdominal CT-guided biopsy specimen revealed a MCC. The patient underwent preoperative chemotherapy followed by a laparotomy and the mass was successfully excised. DISCUSSION: There are two possible explanations for what occurred in our patient. The most plausible theory is the retroperitoneal mass could be a massively enlarged lymph node where precursor cells became neoplastic. This would be consistent with a presumptive diagnosis of primary nodal disease. Moreover, metastasis to the retroperitoneal lymph nodes has been reported as relatively common when compared to other sites such as liver, bone, brain and skin. The less probable theory is the non-described "regression" phenomena of a cutaneous MCC, but we are not found a primary skin lesion. CONCLUSION: Preoperative chemotherapy and excision of the primary tumor is the surgical treatment of choice for retroperitoneal MCC. We propose that further studies are needed to elucidate the true efficacy of chemotherapy in conventional and unconventional patients with MCC.

RESUMO

The micropapillary carcinoma is regarded as an aggressive variant of adenocarcinoma in any location. Histologically is characterized by papillary cell clusters surrounded by clear spaces. The reported proportion of micropapillary carcinoma component to the entire tumor ranged from 5 to 80 percent and no pure cases has been reported. There are near of 130 cases reported to date in colorectum. We experienced a patient with a pure micropapillary carcinoma showing coexpression of CK7, CK20, and absence of CDX2, which had an aggressive neoplasm with extense perineural, vascular and lymphatic invasion also extensive nodal metastasis. The presence of a micropapillary carcinoma in the colorectum seemed to be closely related with nodal metastasis, similar to the case for micropapillary carcinomas in other organs. Therefore, if a micropapillary component is identified in a tumor, particularly in a biopsy specimen, even if the pre-operative diagnosis is a pedunculated early colorectal cancer, should be carefully consider the extent of surgical resection due to the high potential for nodal metastasis.

El carcinoma micropapilar es considerado como una variante agresiva del cáncer en cualquier localización. Histológicamente se caracteriza por grupos de células papilares rodeada de espacios libres. Se informó que la proporción del componente carcinoma micropapilar en la totalidad de un tumor varió entre 5 por ciento a 80 por ciento y no se han reportado casos puros. Existen cerca de 130 casos reportados hasta la fecha en colon y recto. Se describe el caso de un paciente con un carcinoma micropapilar puro que muestra coexpresión de CK7, CK20, y la ausencia de CDX2, que tenía un tumor agresivo con extensa invasión perineural, vascular y linfática además de metástasis nodular extensa. La presencia de un carcinoma micropapilar en la región colorrectal parece estar estrechamente relacionada con metástasis nodular, similar al caso del carcinomas micropapilar en otros órganos. Por lo tanto, si un componente micropapilar se identifica en un tumor, sobre todo en una muestra de biopsia, incluso si el diagnóstico pre-operatorio es un cáncer colorrectal temprano pediculado, se debe considerar cuidadosamente la extensión de la resección quirúrgica debido a la alta probabilidad de metástasis nodular.

Assuntos

RESUMO

A 12-year-old spayed female miniature pinscher canid presented to the referring veterinarian with a 1 month history of a right eyelid mass. No other masses besides a previously diagnosed lipoma were identified after physical examination and thoracic radiographic examination. Histologically, neoplastic cells formed glands and were subdivided by a fibrous stroma, exhibited moderate cellular pleomorphism, and were immunoreactive for cytokeratin 7. Based on these findings an apocrine adenocarcinoma of the eyelid was diagnosed.

RESUMO

A 12-year-old spayed female miniature pinscher canid presented to the referring veterinarian with a 1 month history of a right eyelid mass. No other masses besides a previously diagnosed lipoma were identified after physical examination and thoracic radiographic examination. Histologically, neoplastic cells formed glands and were subdivided by a fibrous stroma, exhibited moderate cellular pleomorphism, and were immunoreactive for cytokeratin 7. Based on these findings an apocrine adenocarcinoma of the eyelid was diagnosed.(AU)

Assuntos