Fig.2
Fig.3
Bibliografia
1. Toker C. Trabecular carcinoma of the skin. Arch. Pathol. 105: 107-110, 1972
2.Maize J et al. Cutaneous Pathology. Churchill-Livingstone, Philadelphia, 1998, pagg. 473-477.
3. C. Urso: A tumour, a cell, a misunderstanding: Trabecular (Merkel cell) carcinoma of the skin. J. Clin. Pathol. 44: 781, 1991.
Fig.1
MERKEL CELL CARCINOMA
(Synonym: Primary neuroendocrine carcinoma of the skin)
Merkel cell carcinoma, first described in 1972 by Toker [1], is an aggressine cutaneous tumor, which can lead to a global martality up to 50%. It generally occurs in sun-exposed areas (head and neck) of elderly patients (VII e VIII decades)[2]. Both the sexes are equally affected; the tumor may be single or multiple; generally, it measures less than 1 cm and shows a pink or red color. It may be ulcerated, with a scalecrust. Because of the histologic features of its cells, an origin from Merkel cells of the epidermis has been proposed, but the normal distribution of such cells does not fit with the common sites in which the tumor really occurs [3]. Moreover, although several histological, ultrastructural and immunohistochemical aspects of the tumor cells are resemblant those of Merkel cells, some differences seem to exist: tumor cells generally express neurofilament proteins, which are absent in normal Merkel cells. Histologically, the tumor is composed of small uniform cells (Fig. 1); a grenz zone between the tumor and the epidermis is observed (Fig. 2). Nuclei of tumor cells are round to oval and mitoses numerous. The tumor stroma is sclerotic. Immunohistochemically, tumor cells express neuron-specific enolase, cromogranin A (Fig. 3), citokeratin 20 and other antigen in variable proportion. The pathological features possibly indicative of an aggressive clinical course are gross size greater than 2 cm, more then 10 mitoses per high power field, lymphatic invasion, and the presence of the "oat cell" growth pattern (resemblant oat cell cancer of the lung). In such cases, a prophylactic regional lymphadenectomy, or more recently, a sentinel lymph node biopsy are recommended. Adjuvant radiotherapy is used in cases with lymph node metastases.
page 13
The other pages
- Home Page: Dermatopathology - C. Urso, MD
- page 1: Melanoma of the skin
- page 2: Histologic diagnosis of cutaneous melanoma
- page 3: Melanoma arising in a melanocytic nevus
- page 4: Infiltration and pseudoinfiltration
- page 5: Sweat gland carcinomas
- page 6: The sentinel lymph node in cutaneous melanoma
- page 7: Bullous cutaneous diseases
- page 8: Spitz nevus
- page 9: Prognostic factors in cutaneous melanoma
- page 10: The dysplastic nevus
- page 11: Dermatofibrosarcoma protuberans
- page 12: Melanoma in situ
- last page: Questions, comments and opinions
page 13: Merkel cell carcinoma
page 14: Basal cell carcinoma
page 15: Melanoma in paediatric age