Langerhans cell histiocytosis: an update

The histiocytoses represent a heterogeneous group of disorders that are characterized by the proliferation and accumulation of reactive or neoplastic histiocytes within various tissues. Langerhans cell histiocytosis (LCH) is the commonest of these disorders and it is associated with high morbidity and mortality, especially in children. LCH is a poorly understood disease with features suggestive of a neoplastic, reactive, or immune dysregulation process. The clinical spectrum of LCH is considered to be broad and includes from self-resolving involvement of a single organ to a potentially fatal multisystem disease. The purpose of this review is to undertake an update of LCH with emphasis on the current recommendations regarding the classification, evaluation and treatment of this enigmatic disease.

Tuberculous empyema necessitatis. A rare cause of cutaneous abscess in the XXI century

A 24-year-old Moroccan man was admitted to the hospital because of a tumor of the abdominal wall, fever, and purulent sputum. Imaging tests showed the presence of a pleural effusion and tumor in the right abdominal wall. The organized collection of liquid in the mass was contiguous with the thoracic collection and that of the subphrenic space. Thoracocentesis removed purulent material suggestive of empyema. Cultures and polymerase chain reaction (PCR) tests confirmed the diagnosis of tuberculous empyema. Empyema necessitatis refers to empyema that extends into the extrapleural space through a defect in the pleural surface. Various infectious etiologies may be responsible. Tuberculous empyema necessitatis is a rare complication of tuberculosis (TB); our case is even more unusual because this condition presented as an abdominal wall abcess and the patient was immunocompetent. His only predisposing factors were his country of origin, where there is a high prevalence of TB and the delay in diagnosis due to a lack of access to health care.

Cutaneous sarcoidosis and polycythemia vera

Polycythemia vera is classified with myelogenous leukaemia, agnogenic myeloid metaplasia and primary thrombocythemia as a myeloproliferative syndrome. Cutaneous symptoms have been reported with polycythemia vera, including facial plethora, aquagenic pruritus, urticaria, purpura, Sweet's syndrome and pyoderma gangrenosum. However, polycythemia vera associated with systemic sarcoidosis has been rarely reported. An unusual case of polycythemia vera associated with cutaneous sarcoidosis is described.

Aquagenic keratoderma

Aquagenic keratoderma has been described as a transitory condition involving young females and defined clinically by the appearance of palmar lesions accentuated after immersion in water. According to previous case reports, these lesions are characterized histologically by hyperkeratosis and dilated eccrine ducts. Some aberration in the eccrine ducts has been suggested as a possible pathogenic mechanism. We report a new case in a female adolescent. With regard to the normal aspect of the epidermis in our case, the clinical changes should be ascribed to a structural alteration of the horny layer without any visible microscopy change or functional alteration of the stratum corneum involving the organism in the adolescence period.

Merkel cell tumor presenting as a painful patch lesion on the right arm

Primary small cell cutaneous neuroendocrine carcinoma (Merkel cell carcinoma) is an uncommon, highly malignant, primary cutaneous neuroendocrine carcinoma. Clinically it is seen as a 0.5- to 5.0-cm pinkish purple papule or nodule, usually not ulcerated, on the head, neck, or, less frequently, the roots of the limbs. We present the case of a woman with an atypical clinical presentation of a Merkel cell tumor.

Relapsing cutaneous alternariosis in a kidney transplant recipient cured with liposomal amphotericin B

An immunosuppressed patient who presented with unusual clinical signs of cutaneous alternariosis, including papular, nodular and verrucous lesions of the forearms, is reported. In spite of continuous treatment with oral itraconazole for 6 months, a large, progressive, necrotic ulcer appeared on the patient's left leg. Liposomal amphotericin B was then administered (total dose, 750 mg) with excellent clinical results.

Acute juvenile pityriasis rubra pilaris: a superantigen mediated disease?

Juvenile acute pityriasis rubra pilaris (JAPRP) is a form of pityriasis rubra pilaris (PRP) with particular clinical characteristics and course. It is usually preceded by an infectious condition. We report a boy, initially thought to have Kawasaki disease, and subsequently diagnosed as having JAPRP, who made a satisfactory recovery. In this case, prior antibiotic treatment made it impossible to show the presence of any microorganism. However, the clinical characteristics of these patients and the similarities with other disorders involving the skin that are mediated by superantigens led us to think that these antigens may be involved in the development of this disease. Also, in view of the obvious differences between JAPRP and the other PRP, we suggest that, in the future this disorder may be considered a separate entity as a reactive exanthem.

Unilateral multiple facial angiofibromas: a mosaic form of tuberous sclerosis

Tuberous sclerosis has many forms of clinical presentation. Rarely, multiple facial angiofibromas of unilateral distribution have been reported. We describe 2 patients with such a presentation and hypothesize that this is a mosaic form of tuberous sclerosis.

Bronchogenic cyst presenting as a nodular lesion

We report a subcutaneous bronchogenic cyst in a 7-year-old girl with unusual presentation as a nodular lesion. The cyst was excised and no connection with deeper structures was found. Histologic examination showed the typical features of a bronchogenic cyst. The characteristic clinical and histologic features of bronchogenic cysts are reviewed. The problems of differential diagnosis are also discussed.