Suat-Hoon Tan

Aggressive subcutaneous panniculitis-like T-cell lymphoma with hemophagocytosis in two children (subcutaneous panniculitis-like T-cell lymphoma)

Subcutaneous panniculitis-like T-cell lymphoma is an uncommon form of cutaneous lymphoma in the pediatric population. It is characterized histologically by subcutaneous infiltration of pleomorphic cytotoxic T cells, mimicking a lobular panniculitis. Although usually described as having an indolent clinical course, the condition may be complicated by systemic involvement and hemophagocytic syndrome, resulting in a poorer prognosis. We present two pediatric patients with aggressive forms of subcutaneous panniculitis-like T-cell lymphoma complicated by hemophagocytic syndrome, and discuss the current literature.

Cutaneous sarcoidosis in Asians: a report of 25 patients from Singapore

Sarcoidosis is a systemic noncaseating granulomatous disorder of unknown origin involving multiple organ systems. There has been no report so far to describe the epidemiological pattern of cutaneous involvement in sarcoidosis in South‐East Asia with diverse ethnic groups. A retrospective study examining the clinicopathological features of all patients diagnosed with sarcoidosis at a tertiary dermatology centre in Singapore from 1980 to 2003 was conducted. Cutaneous sarcoidosis was diagnosed in 25 patients: 13 were Indian, 11 were Chinese and one was Eurasian. Cutaneous manifestations included papules, nodules, plaques and scarring alopecia. Extracutaneous involvement of lymph nodes (four patients), lungs (eight patients) and eyes (two patients) was seen. Eight patients had abnormal chest radiographic findings. Histopathological examination of skin lesions revealed noncaseating, epithelioid granulomatous infiltration in the dermis without evidence of mycobacterial infection, deep fungal infection or polarizable birefringent material. Treatment modalities included corticosteroids, hydroxychloroquine, isotretinoin, methotrexate and surgical excision. Five patients had complete resolution of the cutaneous lesions. Cutaneous sarcoidosis is rare in Asia and indeed in Singapore. Extracutaneous involvement is not uncommon and a thorough clinical evaluation should be undertaken.

Comparative study of pemphigus vulgaris and pemphigus foliaceus in Singapore.

This is a retrospective study of all patients diagnosed to have pemphigus in our centre over a 3 year period. The case records of all patients with pemphigus from January 1995 to December 1997 were analysed. Fifty patients were diagnosed to have pemphigus during the study period. The diagnoses were pemphigus vulgaris in 31 patients, pemphigus foliaceus in 16, paraneoplastic pemphigus in two and IgA pemphigus in one. The average titre of anti‐intercellular antibodies in patients with pemphigus vulgaris (1:96) was higher than the titre in patients with pemphigus foliaceus (1:69). The average initial dose of prednisolone required for disease control in patients with pemphigus vulgaris (62 mg/day) was significantly higher than that required for patients with pemphigus foliaceus (44 mg/day). In our study population, pemphigus vulgaris is a more severe and chronic disease than pemphigus foliaceus, as reflected in the higher titre of anti‐intercellular antibodies, higher dose of systemic corticosteroids required for control of the disease, the longer duration to achieve complete remission and longer follow‐up period.

Comparison of immunofluorescence microscopy, immunoblotting and enzyme-linked immunosorbent assay methods in the laboratory diagnosis of bullous pemphigoid

This prospective study investigated patients with a clinical diagnosis of bullous pemphigoid (BP) who presented to a tertiary dermatology referral centre in Singapore. All patients had blood samples and skin biopsies taken for histology, immunofluorescence (IF) and immunoblot analysis prior to initiation of treatment. We analysed 23 new cases of BP during the 1‐year study period. Seventeen of 22 biopsy specimens showed subepidermal blister formation, and 12 of the 17 (71%) had a predominance of eosinophils (> 50%) in the blister cavity. The dermal inflammatory infiltrate of 22 biopsy specimens was predominantly lymphocytic in nine (41%) and eosinophilic in eight (36%). The histological picture was highly suggestive of BP in 15 of 22 patients (68%), suggestive in two (9%) and poorly suggestive in five (23%). Twenty‐one of 23 (91%) patients had linear deposits of IgG and C3 along the dermo‐epidermal junction. Serum indirect IF was positive in 22 of 23 (96%) patients, all showing antibody binding to the roof of the induced blister on salt‐split skin. All of the 23 serum samples demonstrated positive immunoblot reactivity to BP180 and/or BP230 from epidermal extracts of normal human skin. Immunoblot reactivity with BP180 and BP230 was 78% (n = 18) and 52% (n = 12), respectively. The BP180 NC16A antibody could be detected in 22 of 23 (96%) sera using the enzyme‐linked immunosorbent assay (ELISA) technique. The sensitivity of traditional diagnostic techniques, i.e. direct IF (91%) and indirect IF (96%), was comparable with that of the newer techniques, i.e. immunoblot analysis (100%) and ELISA (96%). ELISA in combination with routine indirect IF may be a useful diagnostic tool in patients with suspected BP who refuse a skin biopsy but consent to give a serum sample.

Squamous cell carcinoma developing in two Chinese patients with chronic discoid lupus erythematosus: the need for continued surveillance

Squamous cell carcinoma (SCC) is a rare late sequel of chronic discoid lupus erythematosus (CDLE). We report two cases of SCC developing in Chinese patients with CDLE. The first patient had prior biopsies from the same site that showed viral warts and the second patient had multiple histologically confirmed viral warts around the vicinity of the previously excised SCC. In this paper, we emphasize the need to be suspicious of warty lesions on skin afflicted by CDLE, and repeat biopsies should be performed if there is failure to respond to conventional therapy.

Pemphigus vulgaris following varicella infection

We describe a 26‐year‐old Indian man who presented with chickenpox and subsequently developed pemphigus vulgaris 17 days after initial resolution of lesions. The mechanism of progression from one disease to the other is postulated to be that of epitope spreading or molecular mimicry.

Melanization in basal cell carcinomas: Microscopic characterization of clinically pigmented and non‐pigmented tumours

Clinical and microscopic pigmentation may affect the treatment outcomes in basal cell carcinoma. However, there have not been any in‐depth histopathological comparisons between clinically pigmented and non‐pigmented basal cell carcinomas with regards to microscopic melanization. The aims of our study were to determine the proportion of pigmented basal cell carcinomas presenting to the National Skin Centre in Singapore, to characterize the histological pattern of melanization and to perform a semi‐quantitative analysis of the degree of microscopic melanization of the tumours. Patients with clinical features and histologically confirmed basal cell carcinomas were recruited. Demographic data and clinical characteristics were recorded and basal cell carcinoma sections were examined for histological subtype and pattern of melanization. Twenty‐five Chinese patients with 30 basal cell carcinomas were recruited. Three of the five clinically non‐pigmented and all of the clinically pigmented basal cell carcinomas had microscopic evidence of melanization. Microscopic melanization in clinically non‐pigmented basal cell carcinomas was present only focally or in the centre of the tumour mass. Both groups of basal cell carcinomas may be colonized by melanocytes. Two morphological types of melanocytes, a dendritic and round cell type, were identified. Future research is required to evaluate if the degree of microscopic melanization influences the treatment outcome of basal cell carcinomas.

Characterization of the inflammatory cell infiltrate in herald patches and fully developed eruptions of pityriasis rosea.

Background.  Pityriasis rosea (PR) is a common cutaneous papulosquamous disorder affecting young adults. Previous studies have suggested possibilities of a viral aetiology and the involvement of cell‐mediated immunity, but these remain unproven to date.

Reticulate hyperpigmented scleroderma: a new pigmentary manifestation

Scleroderma is a systemic disease with a myriad of cutaneous manifestations. Pigmentary disturbances have been described in scleroderma. While diffuse generalized hyperpigmentation and localized hypopigmentation with perifollicular hyper‐pigmentation are well recognized, a vascular induced hyperpigmentation has only been recently described. In this paper, we report another unrecognized pigmentary abnormality in a 48‐year‐old patient who presented with a reticulate hyper‐pigmentation affecting the trunk, upper and lower limbs. To our knowledge, cutaneous hyperpigmented reticulate scleroderma has not been reported previously.

Hypopigmented macular amyloidosis with or without hyperpigmentation.

Primary cutaneous amyloidosis (PCA) is a chronic pruritic skin disorder with characteristic amyloid deposits in the papillary dermis. We report three cases of PCA, which shared common features of hypopigmentation as a predominant feature with or without reticular hyperpigmentation, no itching, adult onset and dermal papillary amyloid deposition. These cases did not conform to the usual features of PCA.