Unilateral linear basal cell nevus associated with diffuse osteoma cutis, unilateral anodontia, and abnormal bone mineralization

Happle-Tinschert Syndrome: A Case Report of Unilateral Segmentally Arranged Basaloid Follicular Hamartoma with Scoliosis and Review of Literature

Happle-Tinschert syndrome is a rare disease characterized by unilateral, segmentally arranged basaloid follicular hamartoma (BFH) with osseous, dental, and cerebral anomalies. Although BFH has been demonstrated to be associated with mutations in the patched gene, the genetic basis for Happle-Tinschert syndrome is still unknown. We describe a case of Happle-Tinschert syndrome in a 26-year-old female. The patient presented with unilateral skin color change to brownish papules and atrophoderma following the development of Blaschko's lines, plantar pitting, and nail dystrophy on the right side of the body. She also had scoliosis, hemihypotrophy, and dental anomalies. The skin lesions were histologically confirmed as BFHs. Next-generation sequencing of the patient's genomic DNA obtained from a peripheral blood sample identified no pathogenic mutation. This case illustrates the characteristic clinical features of Happle-Tinschert syndrome. Thus far, 14 cases of Happle-Tinschert syndrome have been reported, and we report another case of this syndrome.

[Histopathological study of basaloid follicular hamartoma]

INTRODUCTION

Basaloid follicular hamartoma (BFH) is a rare tumor first described in 1985. It bears clinical and histologic similarities with basal cell carcinoma (BCC), in particular the so-called infundibulocystic form. We performed a single-center clinicopathological study of a series of typical cases of this entity that is occasionally difficult to diagnose.

MATERIALS AND METHODS

All cases of BFH seen at the Dermatopathology Laboratory of Strasbourg University Hospital were included and analyzed by means of HE staining and Ber-EP4 and PHLDA1 immunolabelling. Diagnosis was made in the event of basaloid proliferation with anastomosing cords developed from a hair follicle. Clinical data were collected from clinical files.

RESULTS

We identified 15 cases in 13 patients of mean age 44.8 years (range: 4 to 90) and the sex-ratio was 5/8. Lesions consisted of flesh-colored papules measuring 0.3 to 1.2cm in diameter, without any preferential site. Three patients had multiple lesions consisting of several coalescent papules on a breast for one, sparse papules on the back for another, and hundreds of linear unilateral BFHs, associated with osseous abnormalities, characteristic of Happle-Tinschert syndrome, for the third. All tumors were limited to the superficial and mid dermis, with a vertical orientation and connection to the epidermis in 14 of the 15 patients. In some cases, the outermost cells were basophilic while the central cells were eosinophilic. Peripheral palisading and clefting were frequently observed. Keratin cysts or sebaceous ducts were consistently present, indicating follicular differentiation. Ber-EP4+ cells were restricted to the periphery of the cords and PHLDA1 was weakly expressed.

DISCUSSION

BFH is a rare entity that must be differentiated from BCC. It presents as solitary or multiple lesions, either grouped in plaques or with a generalized or linear unilateral distribution. Generalized BFH may be associated with autoimmune diseases and linear unilateral BFH with osseous, dental and cerebral abnormalities in Happle-Tinschert syndrome. It is important to distinguish BFH from BCC to avoid inappropriate aggressive treatment.

Congenital systematized basaloid follicular hamartoma with microphthalmia and hemimegalencephaly

The lines of Blaschko are a cutaneous pattern of mosaicism present in a variety of skin disorders. Developmental abnormalities affecting other tissues derived from the embryonic ectoderm and mesoderm are sometimes associated. Here, we describe a 5-year-old boy with basaloid follicular hamartoma affecting the left side of the body in linear multiple bands, following Blaschko lines. Lesions were predominantly hypopigmented macules and streaks, but among these, we could observe brownish atrophic patches and brown papules. Furthermore, ipsilateral hemimegaloencephaly and microphthalmia were present. These findings suggest a neurocutaneous condition recently described by Happle and Tinschert. Its nosologic classification will be discussed.

[Basal cell carcinoma. Molecular genetics and unusual clinical features]

Basal cell carcinoma is the most common human cancer. Its incidence is steadily increasing. The development of basal cell carcinoma is linked to genetic factors, including the individual skin phototype, as well as the cumulative exposure to UVB. The vast majority of basal cell carcinomas are sporadic tumors, while familial cases associated with certain hereditary syndromes are less common. At the molecular level, basal cell carcinomas are characterized by aberrant activation of sonic hedgehog signaling, usually due to mutations either in the ptch or smoh genes. In addition, about half of the cases carry mutations in the tp53 tumor suppressor gene, which are often UVB-associated C-->T transition mutations. Clinically, basal cell carcinomas may show a high degree of phenotypical variability. In particular, tumors occurring in atypical locations, showing an unusual clinical appearance, or imitating other skin diseases may cause diagnostic problems. This review article summarizes the current state of the art concerning the etiology, predisposition and molecular genetics of basal cell carcinoma. In addition, examples of unusual clinical manifestations are illustrated.

The role of the orthodontist in the diagnosis of Gorlin's syndrome

Gorlin's syndrome is a relatively rare generalized disorder. Its diagnosis in childhood is usually through oral abnormalities. Some of the most frequent clinical features of this syndrome are discovered through radiographs commonly used in orthodontia. Thus, the orthodontist may be able to contribute to its diagnosis. The article shows three clinical cases that illustrate the role that the orthodontist may play in diagnosis of this syndrome.

Congenital plate-like osteoma cutis of the forehead: an atypical presentation form

Cutaneous ossifications or osteoma cutis can be found in many syndromes. Primary osteoma cutis, present since birth or the first months of life, in the absence of metabolic disorders or trauma, is found in congenital plate-like osteoma cutis and progressive osseous heteroplasia, coexisting in the latter with deep connective tissue ossifications. This report documents the case of a 7-year-old female with a plate-like cutaneous ossification of the forehead causing aesthetic deformities. Other dermal ossifications in the inguinal and preauricular region, as well as the left hand and a small focus in the extraocular muscles of the left orbit, were also present. These lesions did not show progression, and most of them were present since birth. The lesion of forehead was treated surgically. The lack of progression and the fact that the orbital lesion was solitary still fits the criteria for the diagnosis of plate-like osteoma cutis. Plate-like osteoma cutis and progressive osseous heteroplasia may represent varieties of the same disorder.

Primary osteoma cutis--multiple café-au-lait spots and woolly hair anomaly

An 11-year-old girl with typical features of primary osteoma cutis is reported. She demonstrated multiple areas of subcutaneous, asymptomatic, slow-growing nodules, mostly localized at the extremities. Radiographic evidence of soft tissue calcification and histologic confirmation of ectopic bone formation was obtained. She also showed café-au-lait spots, woolly hair and intrauterine growth deficiency.

Lines of Blaschko

The lines of Blaschko represent a pattern followed by many skin disorders. We review the clinical and histologic features of X-linked, congenital/nevoid, and acquired skin diseases that follow these lines. We also include cutaneous disorders that have a linear distribution but do not follow Blaschko's lines. Finally, we differentiate Blaschko's lines from other patterns on the skin such as dermatomes and Langer's lines.

Localized hair follicle hamartoma

A 4-year-old male presented with an indurated papular plaque on his right nasolabial fold. The lesion, present since the child was a few months of age, progressively extended in a band-like fashion up to the upper lip. Microscopically, there was almost complete replacement of the hair follicles by trichoepithelioma-like epithelial proliferations associated with hyperplastic sebaceous glands. We interpret this lesion as a localized form of the clinicopathological entity known as generalized hair follicle hamartoma.

Congenital platelike osteoma cutis: case report and review of the literature

An 18-year-old girl had a progressive enlarging plate of subcutaneous bone in the scalp since birth. Histologic examination of the lesion showed typical osteoma cutis. There was no history of any skin disease prior to development of the osteoma. Frequently congenital and usually located on the scalp, platelike osteoma is a rare variant of osteoma cutis.

Skin and bones. II

Skin disorders in which a radiograph may detect associated bony changes or abnormalities of calcification are discussed. They are grouped into eight categories: (1) inherited diseases (e.g., alkaptonuria, neurofibromatosis); (2) congenital disorders (e.g., Sturge-Weber and Proteus syndromes); (3) inflammatory conditions (e.g., dermatomyositis, sarcoidosis); (4) infections (e.g., dental sinus, syphilis); (5) neoplasias (e.g., histiocytosis, mastocytosis); (6) drug- and environment-induced (e.g., acroosteolysis, retinoid toxicity); (7) calcinosis cutis; and (8) osteoma cutis. The first part of this review, published in the August 1991 issue of this JOURNAL, dealt with the first two categories; part II discusses categories 3 through 8.