Neurological symptoms in a patient with large congenital melanocytic naevus are highly suggestive of cerebromeningeal melanoma metastasis. The presence of melanocytic cells in cerebrospinal fluid confirms this diagnosis If their malignant nature is shared with cutaneous naevocytic cells. Conversely, neurocutaneous melanosis is diagnosed when benign melanocytosis meningitis is found in patients with multiple and/or large congenital melanocytic naevus, whether cutaneous naevus cells are benign or not, or when cerebrospinal fluid cells are malignant with benign cutaneous melanocytic naevus. We report the case of a young man aged 19 presenting with multiple and large congenital melanocytic naevus who experienced transcient neurological signs and increased intracranial pressure. Cerebral neuroimaging evoked meningeal infiltration which benign melanocytic nature was supposed on CSF analysis and confirmed by necropsy findings, only 3 month after neurological onset, leading to neurocutaneous melanosis diagnosis. This rare neuroectodermal dysembryoplasia finds expression in various neurological signs, depending on patient's age and leptomeningeal and/or cerebral proliferation localization. Lumbar puncture, cerebral scanography and MRI may help diagnosis, but only histological examination can prove neurocutaneous melanosis, more often by necropsy because of poor prognosis.

Maffucci syndrome is a rare dysembryoplasia associating cartilage tumors similar to enchondromas in Ollier's disease and vessel tumors. We report the case of a 50-year-old woman with Maffucci syndrome involving the lower legs who developed a variety of vascular proliferations. This patient had capillary hemangiomas, cavernous angiomas, and lymphangiomas facing the cartilage tumefactions on the thigh. Regular clinical surveillance is required for such patients due to the risk of degeneration of the enchondromas and the angiomas, but also due to the possible occurrence of other malignant tumors besides the cartilage and vessel tumors.

Maffucci's syndrome is a dysembryoplasia of the mesoderm, explaining the dual involvement of cartilage and vascular tissue. The risk of malignant degeneration or associated tumors is high in this uncommon disease. We report a case of Maffucci's syndrome associated with squamous cell carcinoma of the cavum.A 37-year-old man consulted for multiple angiomas and chondromas which had developed since childhood. The diagnosis of Maffucci's syndrome was obvious. Radiological exploration of the limbs confirmed chondromatosis and biopsy of the cavum performed because of the occurrence of epistaxis, revealed squamous cell carcinoma.Maffucci's angiochondromatosis is a rare, non-hereditary but sometimes congenital disease. Angiomas predominate on the hands and feet. Sarcomatous degeneration is the main complication of these chondromas. Angiomas rarely become malignant, but when they do are generally more aggressive than chondromas. The frequency of neoplasia in Maffucci's syndrome would suggest that there is a supplementary oncogenic factor. Several types of malignancy associated with Maffucci's syndrome have been reported, but to our knowledge there has been no publication concerning an association between Maffucci's syndrome and squamous cell carcinoma of the cavum.

Cysts and canals found on the ventral surface of the penis have been ascribed to minor dysembryoplasia of the male genitalia. These lesions occur almost exclusively on the ventral surface of the penis along the median raphe and can extend from the urethral meatus to the anus. They are lined by stratified urothelium or squamous epithelium and they do not communicate with the urethra. Most cases are noted in early adulthood, they are usually asymptomatic but may become infected. Surgical removal is the adapted treatment. In this report we describe a case in which the urothelial origin of the cyst was documented by immunohistochemistry for cytokeratin 13.

Maffucci's syndrome was first described in 1881 and results of a mesodermic dysembryoplasia, congenital but not hereditary. Pathogenic hypothesis are multiple. This syndrome is characterized by the occurrence of multiple haemangiomas in the soft tissue, and multiple enchondromas of the bones. The association of ovary tumor is however exceptional. Four cases are reported in the literature; we report the fifth case.

Primary osteoma cutis arises in the deeper dermis for no apparent reason and presents as mature, lamellar, and osteonic bone; secondary cutaneous osteomas are correlated with inflammatory processes, scars, or dysembryoplasia and are always composed of osteoid. Ultrastructural findings of primary cutaneous osteomas have not been reported to date. Light and electron microscopic findings of a case of primary osteoma cutis are described: mineralized areas may be divided into macrocalcification and microcalcification. Macrocalcification consists of lamellar bone. Osteocytes populate the lamellae, whereas collagen fibril distribution is bone-like. Hydroxyapatite deposition presents as globular or needle-like electron-dense material progressively masking the connective tissue matrix. Microcalcifications, which are found in macroscopically normal dermis around the calcified plaque, consist of osteoid tissue inhabited by osteoblast-like cells. Microcalcifications may be interpreted as metastatic calcifications related to the primary osteoma calcified plaque. Primary osteoma cutis may be considered as true bone amartothic formation rather than dermal mineralization.

Smooth muscle hamartoma is an uncommon cutaneous dysembryoplasia usually diagnosed in infancy. Among the 61 cases published since 1923, 56 were congenital and 3 appeared in young adults. We report a case in which the lesions started at the age of 15 years as a papular plaque in the right mammary region of a young woman. A review of the literature showed that the usual clinical presentation is a frequently pigmented plaque made of often follicular papules and measuring 1 to 10 centimeters on average. Excessive hairiness is the most frequent sign, being observed in more than two-thirds of the cases, and Darier's pseudo-sign is present in about 53 p. 100 of the patients. The disease is electively located on the lumbar region, the back and the root of the limbs. In 3 cases the lesions were generalized and the patients looked like fatty "Michelin-Tire Babies". The course of the disease is always favourable, and associated pathologies remain exceptional: urticaria pigmentosa and psychomotor retardation have been reported in two cases of the generalized form. Histology is characterized by the presence of numerous smooth muscle fibres disseminated in the dermis and diversely oriented, sometimes in contact with hair follicles which retain their normal morphology. The differential clinical diagnosis is with naevocytic naevus, café-au-lait spots, mastocytosis and connective tissue hamartoma. Belatedly revealed forms of the disease must be distinguished from Becker's hamartoma, but it must be known that in certain cases the classification is so difficult that some authors have suggested that smooth muscle hamartoma and Becker's hamartoma are only two poles of a single spectrum of dysembryoplastic lesions involving to varying degrees the epidermic and hair structures. Finally, the distinction between the localized forms of late onset smooth muscle hamartoma and multiple leiomyomas "en plaques" remains difficult both anatomico-clinically and nosologically.

The published 9th case of circumscribed pilary dysembryoplasia of the palms is presented. Differences between this case and Becker's pigmented hair nevus, congenital smooth muscle hamartoma, circumscribed acquired hypertrichosis and pigmented nevus are discussed.

Perineo-gluteal hidradenitis suppurativa, or Verneuil's disease, consists of infected and more or less fistulized lesions unconnected with the anal canal, dermo-epidermal nodule and diffuse subcutaneous infiltration. The disease is chronic with acute episodes and periods of stabilization and it interferes with the patient's daily life. The lesions originate in the apocrine sweat glands which are predominantly located in the inguinal, perineal and gluteal regions but may also be found in the axillary, areolar and periumbilical regions. The cause of the disease is unknown, but it has been attributed to an anaerobic Streptococcus, to hormonal factors or to maceration or dysembryoplasia. Treatment consists of wide excision of the lesions followed by a network of skin grafts after a granulation period. Isotretinoin has not yet been proved effective.