Actualización en el carcinoma de células de Merkel: claves de las técnicas de imagen, factores pronóstico, tratamiento y seguimiento / Merkel cell carcinoma: an update of key imaging techniques, prognostic factors, treatment, and follow-up

El carcinoma de células de Merkel es un tumor muy poco frecuente, pero es uno de los más agresivos a los que se puede enfrentar un dermatólogo. Más de un tercio de los pacientes fallece por esta enfermedad. Numerosos investigadores han intentado identificar los posibles factores clínico-patológicos relacionados con el pronóstico de este carcinoma. Sin embargo, los resultados obtenidos en estos estudios son discordantes. Debido a la baja frecuencia y la edad avanzada de los pacientes, no se dispone de estudios prospectivos, y en consecuencia, no existe un claro algoritmo en el tratamiento. Este artículo pretende realizar una exhaustiva y comprensiva revisión del carcinoma de células de Merkel que suponga al dermatólogo una puesta al día en este tumor. Detallamos los factores pronósticos, se revisan las técnicas de imagen que resultan más adecuadas para el estudio de extensión y las controversias actuales relacionadas con el tratamiento

Merkel cell carcinoma, though rare, is one of the most aggressive tumors a dermatologist faces. More than a third of patients with this diagnosis die from the disease. Numerous researchers have attempted to identify clinical and pathologic predictors to guide prognosis, but their studies have produced inconsistent results. Because the incidence of Merkel cell carcinoma is low and it appears in patients of advanced age, prospective studies have not been done and no clear treatment algorithm has been developed. This review aims to provide an exhaustive, up-to-date account of Merkel cell carcinoma for the dermatologist. We describe prognostic factors and the imaging techniques that are most appropriate for evaluating disease spread. We also discuss current debates on treating Merkel cell carcinoma

Merkel Cell Carcinoma: An Update of Key Imaging Techniques, Prognostic Factors, Treatment, and Follow-up. / Actualización en el carcinoma de células de Merkel: claves de las técnicas de imagen, factores pronóstico, tratamiento y seguimiento.

Merkel cell carcinoma, though rare, is one of the most aggressive tumors a dermatologist faces. More than a third of patients with this diagnosis die from the disease. Numerous researchers have attempted to identify clinical and pathologic predictors to guide prognosis, but their studies have produced inconsistent results. Because the incidence of Merkel cell carcinoma is low and it appears in patients of advanced age, prospective studies have not been done and no clear treatment algorithm has been developed. This review aims to provide an exhaustive, up-to-date account of Merkel cell carcinoma for the dermatologist. We describe prognostic factors and the imaging techniques that are most appropriate for evaluating disease spread. We also discuss current debates on treating Merkel cell carcinoma.

Estudio de los factores histológicos asociados a la infiltración en profundidad en el dermatofibrosarcoma protuberans / Histologic Features Associated with Deep Invasion in Dermatofibrosarcoma Protuberans

INTRODUCCIÓN: El dermatofibrosarcoma protuberans (DFSP) es un raro tumor cutáneo de crecimiento lento e infiltrativo que alcanza el tejido celular subcutáneo, el tejido muscular e incluso el hueso. OBJETIVOS: Buscar las características histológicas asociadas a una mayor agresividad local en los DFSP, en forma de afectación en profundidad. MATERIAL Y MÉTODOS: Se relacionó las características histológicas propias del DFSP (forma de infiltrar el tejido celular subcutáneo, patrón histológico, tipo celular, áreas de fibrosarcoma) con la presencia o ausencia de afectación de la fascia muscular. RESULTADOS: Se incluyeron 155casos de DFSP. Las características histológicas asociadas significativamente con la afectación de la fascia muscular fueron: el patrón histológico en sábana, un alto grado de pleomorfismo celular y la presencia de más de una mitosis. En la mayoría de los casos (62,6%) el tumor se limitó al tejido celular subcutáneo, en 17 casos (11%) contactó con la fascia muscular o con la galea aponeurótica, y en 36 casos (23,2%) afectó al tejido muscular. CONCLUSIONES: Es importante tener en cuenta el patrón histológico, el pleomorfismo y el número de mitosis en los DFSP para predecir su afectación en profundidad (fascia o músculo), que puede llegar al 30% de los casos

BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) is a rare, slow-growing cutaneous tumor that can invade the subcutaneous tissue, muscle tissue, and even bone. OBJECTIVE: To identify histologic features associated with greater depth of invasion, i.e., local aggressiveness, in DFSP. MATERIAL AND METHODS: We analyzed associations between histologic features of DFSP (e.g., type of subcutaneous invasion, histologic pattern, cell type, areas of fibrosarcoma) and the presence and absence of muscle fascia involvement. RESULTS: We studied 155 cases of DFSP. The following histologic characteristics were significantly associated with involvement of the muscle fascia: the presence of a sheetlike pattern, a high degree of cellular pleomorphism, and more than 1 mitotic figure. The tumor did not extend beyond the subcutaneous tissue in the majority of cases (62.6%), but there was involvement of the fascia or galea aponeurotica in 17 cases (11%) and of the muscle tissue in 36 cases (23.2%). CONCLUSIONS: Histologic patterns, degree of pleomorphism, and number of mitotic figures are important predictors of deep invasion (fascia or muscle) in DFSP; these layers can be involved in up to 30% of cases

Histologic Features Associated with Deep Invasion in Dermatofibrosarcoma Protuberans. / Estudio de los factores histológicos asociados a la infiltración en profundidad en el dermatofibrosarcoma protuberans.

BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) is a rare, slow-growing cutaneous tumor that can invade the subcutaneous tissue, muscle tissue, and even bone. OBJECTIVE: To identify histologic features associated with greater depth of invasion, i.e., local aggressiveness, in DFSP. MATERIAL AND METHODS: We analyzed associations between histologic features of DFSP (e.g., type of subcutaneous invasion, histologic pattern, cell type, areas of fibrosarcoma) and the presence and absence of muscle fascia involvement. RESULTS: We studied 155 cases of DFSP. The following histologic characteristics were significantly associated with involvement of the muscle fascia: the presence of a sheetlike pattern, a high degree of cellular pleomorphism, and more than 1 mitotic figure. The tumor did not extend beyond the subcutaneous tissue in the majority of cases (62.6%), but there was involvement of the fascia or galea aponeurotica in 17 cases (11%) and of the muscle tissue in 36 cases (23.2%). CONCLUSIONS: Histologic patterns, degree of pleomorphism, and number of mitotic figures are important predictors of deep invasion (fascia or muscle) in DFSP; these layers can be involved in up to 30% of cases.

Hiperpigmentación facial parcheada / Patchy Facial Hyperpigmentation

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Mohs micrographic surgery in dermatofibrosarcoma protuberans allows tumour clearance with smaller margins and greater preservation of healthy tissue compared with conventional surgery: a study of 74 primary cases.

BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) is an uncommon skin tumour with aggressive local growth. Whether DFSP should be treated with conventional surgery (CS) or Mohs micrographic surgery (MMS) has long been a topic of debate. OBJECTIVES: To calculate, in a large series of DFSP treated by MMS, the minimum margin that would have been needed to achieve complete clearance by CS. Secondly, to calculate the percentage of healthy tissue that was preserved by MMS rather than CS with 2- and 3-cm margins. METHODS: The minimum margin was calculated by measuring the largest distance from the visible edge of the tumour to the edge of the definitive surgical defect. Tumour and surgical defect areas for hypothetical CS with 2- and 3-cm margins were calculated using AutoCAD for Windows. RESULTS: A mean minimum margin of 1·34 cm was required to achieve complete clearance for the 74 tumours analysed. The mean percentages of skin spared using MMS rather than CS with 2- and 3-cm margins were 49·4% and 67·9%, respectively. CONCLUSIONS: MMS can achieve tumour clearance with smaller margins and greater preservation of healthy tissue than CS.

Positive margins in excised dermatofibrosarcoma protuberans: a study of 58 cases treated with slow-Mohs surgery.

BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) is characterized by unpredictable subclinical extension, meaning that positive margins are frequently detected following conventional surgical excision. OBJECTIVE: To study the presence or absence of residual tumour in DFSP with positive margins after conventional surgery and identify possible predictors of residual tumour or clear margins following a single Mohs micrographic surgery (MMS) stage. METHODS: A retrospective study of patients with DFSP and positive margins following conventional excision referred for MMS was performed. We studied gender, age, tumour site, time from presentation to diagnosis, and affected margins. RESULTS: We studied 58 cases, 35 (60.3%) of which had histological evidence of residual tumour. Tumours of the head and neck were significantly associated with the persistence of tumour. A single MMS stage was sufficient to achieve clearance in the majority of cases (n = 46). All tumours with lateral involvement only were resolved with a single Mohs stage. CONCLUSIONS: DFSPs with positive margins after conventional surgical excision should undergo re-excision because the majority have histologic evidence of residual tumour. Re-excision with 1-cm margins beyond the scar could be an option in certain tumour sites, particularly when it is known which margins are involved.