Indeterminate cell histiocytosis in a Chinese patient with progressive and extensive nodular lesions and mixed indeterminate cell and macrophage-monocyte lineage.

Indeterminate cell histiocytosis (ICH) is an extremely rare cutaneous neoplastic disorder. It has the immunophenotypic features of both Langerhans and non-Langerhans cell histiocytosis. We report here a case of a healthy young Chinese woman who presented with disfiguring, thick, infiltrated cutaneous nodules on the face, trunk and extremities which appeared progressively over a period of 4 years. No systemic involvement has been detected so far. Results of a skin biopsy showed diffuse dermal infiltration of histiocytoid cells with indented nuclei and positive staining for S100 and CD1a and negativity for CD207 (langerin). Admixed within were some CD68-positive foamy histiocytes and multinucleated giant cells with focal expression of CD163. Although the clinical presentation is more typical of progressive nodular histiocytosis, the histology and immunoprofile is consistent with ICH. Our report adds to the limited case reports in the current literature of ICH in the Chinese population.

Current treatment strategies in pediatric alopecia areata.

Alopecia areata (AA) is a non-scarring autoimmune disease of the hair follicle that can present at any age. Pediatric cases are commonly seen in a dermatology clinic, and management can potentially be challenging, with a small proportion of cases experiencing a chronic relapsing course marked by distressing hair loss that can bring about significant psychosocial morbidity. We review the established treatments for pediatric alopecia areata, alongside second and third line therapies that have shown to be efficacious. We also offer a treatment algorithm as a guide to the treatment of pediatric AA.

Extramammary Paget disease: Immunohistochemistry is critical to distinguish potential mimickers.

Extra-mammary Paget disease (EMPD) is a rare intra-epithelial carcinoma that is usually found on the apocrine-rich skin of the perineum. We report 2 cases in which EMPD was initially misdiagnosed on the initial punch biopsy as melanoma-in-situ and Bowen disease respectively. Reasons for the misdiagnoses included a rare pigmented axillary variant of EMPD in the first case and atypical bowenoid features on H&E in the second. The cases are described with a critical review of the histopathological findings, along with a review of the current literature. This highlights the necessity of a comprehensive immunohistochemical panel for the assessment of intra-epithelial pagetoid atypical cells.

Extensive hyperpigmented plaques in a chinese singaporean woman: a case of cutaneous plasmacytosis.

Cutaneous plasmacytosis is a rare disease entity presenting with multiple extensive red-brown plaques, histopathology showing marked hyperplasia of mature polyclonal plasma cells, and polyclonal hypergammaglobulinemia on serum protein electrophoresis, in the absence of an underlying secondary cause. We report in this article the first case of cutaneous plasmacytosis from Singapore. A 33-year-old Chinese woman presented with mildly pruritic reddish brown papules and plaques over her trunk and arms for 2 years. Physical examination, laboratory investigations, and radiographic examination were negative for systemic involvement and lymphadenopathy. Serum immunoelectrophoresis showed polyclonal hypergammaglobulinemia with immunoglobulin G and immunoglobulin A. Two sets of skin biopsies performed 2 years apart essentially showed similar histopathological findings of a superficial and deep perivascular infiltrate with numerous mature plasma cells and small typical lymphocytes. There were lymphoid follicles with well-formed germinal centers and mantle zones, surrounded by mature lymphocytes. No light chain restriction was present on immunohistochemistry, and polymerase chain reaction for heavy chain gene rearrangement was negative for monoclonality. Despite potent topical corticosteroids and 8 months of phototherapy with narrow band ultraviolet light, there was no improvement. Intralesional triamcinolone injections to a few lesions afforded temporary relief of itch and flattening of lesions.

Treatment of pseudofolliculitis in trichotillomania improves outcome.

Trichotillomania is an impulse-control disorder. The underlying psychiatric comorbidity or functional impairment is well recognized by clinicians. Patients with trichotillomania pull their scalp hairs, resulting in damaged, distorted hair follicles, and broken hair shafts within the skin. The local irritation and inflammation resulting from reaction to the broken, impacted hair shafts and malaligned regrowing hair can lead to pseudofolliculitis, much the same as a patient who waxes or shaves her legs gets itchy papules of pseudofolliculitis. Pseudofolliculitis becomes an organic reason for scalp itch and discomfort, and contributes further to the vicious cycle of itch and scratching in trichotillomania. This phenomenon has not been well documented. Treatment of trichotillomania would be more effective if the pseudofolliculitis component is addressed. We describe a series of patients with trichotillomania and pseudofolliculitis. These patients improved after topical steroid therapy, topical or oral antibiotics. Hair regrowth was also visibly better, with patients reporting improvement of symptoms of itch. All these patients were not placed on antidepressants nor antipsychotics.

Progressive trichodysplasia spinulosa in a patient with chronic lymphocytic leukaemia in remission.

A 70-year old Caucasian man with chronic lymphocytic leukaemia developed trichodysplasia spinulosa 2 months after ceasing chemotherapy. Histological features characteristic to this condition include dilated and enlarged hair follicles, hyperplastic hair bulbs, hyperplasia of inner root sheath cells with numerous large, eosinophilic, trichohyaline granules, and hypercornification. Although he was in remission for chronic lymphocytic leukaemia, lesions were slowly progressive 15 months after cessation of chemotherapy. We also describe a painless pull-test where spicules can be easily plucked and assessed microscopically for inner root sheath keratinization, or observed with surface microscopy in a clinic setting.