R. Cerio

Characterization of factor XIIIa positive dermal dendritic cells in normal and inflamed skin

The immunocytochemical identification and characterization of indigenous dermal dendritic cells (dermal dendrocytes) using a rabbit polyclonal antibody to clotting enzyme factor XIII subunit A (FXIIIa) was carried out on normal and inflamed human cutaneous tissue. The immunophenotype of FXIIIa positive dendritic cells was analysed with a panel of 18 monoclonal antibodies using immunoperoxidase and double immunofluorescence staining techniques.

Histiocytoma cutis: a tumour of dermal dendrocytes (dermal dendrocytoma)

The histogenesis of histiocytoma (dermatofibroma) was investigated using new antibodies that demonstrate factor XIIIa (FXIIIa) positive cells and the monocyte macrophage cell series (MAC 387), in formalin fixed tissue. The distribution of S100 protein, vimentin and Ulex europaeus agglutinin 1 (UEA‐1) were also studied. The antibody against FXIIIa labelled the normal dermal population of fixed connective tissue cells (dermal dendrocytes) emphasizing their dendritic processes; cells that are widely distributed, but are most numerous in the papillary dermis. In contrast, the antibody, MAC 387 against monocyte derived macrophages, did not label this cell population.

Epithelioid cell histiocytoma—a new entity

This is a report of a previously undescribed type of histiocytoma distinguished clinically by its occurrence as a solitary elevated nodule often with a vascular appearance and cytologically by the presence of large angulated epithelioid cells. Nineteen lesions from 11 women and eight men have been studied. The lower limb was the commonest site for the nodules. The mean age at presentation was 42 years (range 23–63). Only one lesion recurred after attempted removal. This lesion in the past may, have been mistaken for a Spitz naevus.

Multinucleate cell angiohistiocytoma: an acquired vascular anomaly to be distinguished from Kaposi's sarcoma

Multinucleate cell atigiohistiocytoma is a newly described benign vascular condition that usually arises on the extremities of women over the age of 40 as discrete grouped violaceous erythematous papules, often mimicking Kaposis sarcoma. Of 10 patients, nine were women aged between 37–66 (average 51.5) years at the onset of their condition. The legs, and in particular the calves and thighs, were the commonest sites to be involved. However, in three patients the papules were confined to the back of the hands, and the male patient had lesions across the front of the chest. Bilateral lesions occurred in four patients. Histologically, the salient features were proliferation of capillaries and small venules at the level of the subpapillary plexus and the mid dermis, in association with prominent connective tissue cells and larger angulated multinucleate cells. Detailed histochemical and immunocytochemical studies have not elucidated the histogenesis of the multinucleate cells that seem to be a characteristic feature of this condition.

An immunohistochemical study of fibrous papule of the nose: 25 cases

Twenty‐five cases of fibrous papule of the nose were studied by light microscopy and by immunohistochemistry using a panel of 4 cell markers. These included polyclonal antibodies against S100 protein and Factor XII‐a (FXIII‐a), and 2 monoclonal antibodies, MAC 387 which labels monocyte derived macrophage cells and Ulex Europaeus Agglutinin‐1 (UEA‐1) a pan endothelial cell marker. An increase in the number of S100 protein positive cells, particularly in the upper dermis, was observed in 3 lesions. Melanin was identified in phagocytes in the superficial dermis in 6 lesions, including those with S100 protein positive cells. In all of the papules there was a marked increase in FXIII‐a labelling of dendritic connective tissue cells, including spindle, stellate and multinucleate stellate cells. Immunoreactivity with FXIII‐a was especially strong in the increased mononuclear dendritic cell population (<80%) seen in the mid‐and upper dermis. However, only 15% of the larger multinucleate stellate cells were immunostained with FXIII‐a. The results achieved with markers to the macrophage cell series (MAC 387) or endothelial cells (UEA‐1) showed no significant increase in labelling of the dermal cell population compared to normal skin taken from the nose. Our study suggests that fibrous papule of the nose, a lesion of uncertain histogenesis, probably represents a proliferative reactive process consisting mainly of dermal dendritic cells as identified by FXIII‐a in most of the lesions. There is some evidence that a small percentage of the dendritic cells may represent involuted that a small percentage of the dendritic cells may represent involuted naevi and be of melanocytic origin.

A clinicopathological study of reactive perforating collagenosis: report of 10 cases

The histogenesis of 10 patients with reactive perforating collagenosis (RPC) has been studied. All patients had had recurrent keratotic papules on exposed surfaces leaving varioliform scars since childhood. Seven patients were male and three female, ages ranging from 9–56 years (median 24 years) at presentation. Seven patients were Caucasian (two Portuguese) and three Asian. A familial history of RPC was obtained in two patients. The hands, forearms and, less frequently, the legs, face and trunk were affected. A striking event in one patient was the occurrence of widespread eruptive lesions of RPC on the trunk and limbs, following total body irradiation and cytotoxic therapy for leukaemia.

A clinicopathological and immunohistochemical study of angiolymphoid hyperplasia with eosinophilia

The clinicopathological data from 103 cases of angiolymphoid hyperplasia with eosinophilia (ALHE) have been analysed. The patients included 70 females and 33 males, with a mean age at presentation of 34 years. Most cases presented with either superficial multiple angiomatous papules around the ears or with deep-seated single or multiple nodules on the scalp, face or neck. Unusual sites of involvement included the popliteal fossa, penis, salivary tissue, trapezium muscle and finger. In nearly half the patients with subcutaneous lesions there was involvement of large arterial vessels. In order to analyse the immimolabelling of the abnormal vessels and cellular infiltrate, an immunohistochemical study using 12 cell markers was performed on 21 biopsy specimens from 13 selected cases. Both superficial and deep lesions were included. Endothelial cell markers included F VIII RA, lectin UE Agg-i, EN4 and PAL E. Infiammatory cell markers included UCHLi (T cells), 4KB5 (B cells), MAC 411 (monocyte dermal macrophages), DA 6.231 (Class II antigen), Sioo protein (Langerhans cells), F Xllla (dermal dendrocytes), chloroacetate esterase (mast cells and neutrophil precursor) and vimentin (mesenchymal cells). The results showed labelling of the abnormal vessels in ALHE with all endothelial cell markers. There was some loss of immunoreactivity with F VIII RA and PAL E compared with UE Agg-i and EN4 suggesting that the predominant vessels are venular capillaries. Approximately 80% of the mononuclear cells were T cells and 15 % B cells. Follicular formation resembling early germinal centres was only seen in deeper lesions. Small numbers of MAC 411, SIOO and chloroacetate esterase positive cells were also foimd. The number of dermal dendrocytes and Class II antigen positive cells was greatly increased. These findings support the suggestion that ALHE is not a tumour, but an immunological reaction against an, as yet, imknown antigen. Possibly the pathogenesis involves a combination of both type IV and type I hypersensitivity reactions.

(2) Desmoplastic melanoma: a rare form of malignant melanoma that is usually mis‐diagnosed and mis‐managed

Pretibial epidermolysis bullosa (EB) is a rare variant of dominant dystrophic epidermolysis bullosa (DDEB) with distinct clinicopathological features. We have studied three families with this condition and one further case which was undiagnosed until the eighth decade of life. Clinical details of 25 other affected family members were obtained from the seven cases examined. All the families exhibited an autosomal dominant pattern of inheritance with a male preponderance of 2: i. The age of onset varied widely from 5 days to 25 years, but was consistent within families. The mean age for diagnosis of the probands was 42 years. Two patterns of clinical disease were observed. Cases with early onset disease (< i year) exhibited blistering and shearing of the skin in response to trauma of the lower legs during childhood. Cases with late onset disease (> 10 years) exhibited nail dystrophy with pruritic papulo-nodular lesions in the pretibial sites. Involvement of other sites was rare, apart from the presence of albopapuloid lesions in four of the seven cases examined. Subepidermal clefts were commonly seen in biopsies of involved skin even in the absence of blistering. Our data confirms that pretibial EB is a rare variant of DDEB with atypical clinical features which can cause considerable delay in diagnosis.

3) A clinicopathological study of cutaneous Mycobacterium marinum (Balnei) infection (fish tank granuloma)

Sixteen female patients with primary RP were recruited. The diagnosis was established by clinical evaluation and screening investigations. The response of the digital cutaneous blood flow to a single application of an aliquot of HN lotion (i%) was determined by laser Doppler velocimetry (LDV). Each subject was treated double-blind for 12 weeks, during the winter months of 1987-1988, with one of four lotions, crossing over every 3 weeks. Patients were seen at 3-weekly intervals. The lotions consisted of 1% HN, 2% HN and two placebo formulations containing vehicle alone (Dermal). Patients applied a thin smear of the lotion to the surface of the hands in anticipation of cold challenges. The subject recorded each day on a diary card the frequency, the duration (min), the severity (nil, mild, moderate, severe), the pain (nil, mild, moderate, severe) of attacks, the number of applications of lotion and the ambient temperature (degrees centigrade). Use of the i % HN lotion significantly reduced the mean frequency of attacks of RP per week compared with vehicle and compared with the 2% lotion (P<OO5). Five out of 10 patients experienced side-effects (burning and redness at application sites). We have shown that topical NH lotion (1%) is an effective, convenient and well-tolerated treatment for RP.

15) The immunohistochemistry of systemic follicular lymphoma with cutaneous involvement

Summaries of posters rarely caused by the benzophenones, though mexenone and dioxybenzone have been more commonly reported than oxybenzone. Sunscreen agents are now used in a number of facial cosmetic creams to protect skin from actinic damage and premature ageing. With facial photodermatoses, the appropriate patch tests and photopatch tests with a number of chemicals are indicated, including oxybenzone.