Wong-type dermatomyositis: a mimic of many dermatoses.

Wong-type dermatomyositis (DM) is a rare variant characterized by keratotic follicular papules that may mimic pityriasis rubra pilaris. Histopathologic examination shows follicular and non-follicular epidermal invaginations filled with keratin. The diagnosis is often delayed. Twenty-four cases of Wong-type DM have been reported thus far in the literature. Herein, we report the clinical and histopathologic findings of three additional cases in order to raise awareness of the disorder.

Cutaneous metastasis as the presenting sign of papillary thyroid carcinoma.

Cutaneous metastasis of visceral tumors accounts for 2% of skin tumors. We report the case of a 71-year-old male with a smoking history who presented to dermatology department with a violaceous nodule of the right sideburn skin. The lesion was interpreted as an adenocarcinoma that was completely excised and was suspicious for a metastasis. There was a recommendation for additional work-up. At a different institution, a positron emission tomography scan showed a left hilar mass and uptake in the right thyroid. He was then referred to our hospital for tissue diagnosis. Mediastinoscopy with biopsy of the left hilar mass showed metastatic follicular thyroid carcinoma. Subsequently, a thyroid fine needle aspirate showed suspicion for malignancy with similar morphology. Thyroidectomy and central neck dissection showed right thyroid papillary carcinoma extending to one margin and involving the lymph nodes. The left hilar metastasis mass resection showed similar lymph node findings. A re-review of the sideburn excision revealed similar histopathology to the thyroid and mediastinal resection. This case illustrates the opportunity of considering metastatic thyroid carcinoma to skin even in cases which lack the classic cytologic and architectural features of papillary thyroid carcinoma follicular variant.

A case of pemphigus herpetiformis occurring in a 9-year-old boy.

Pemphigus herpetiformis (PH) is a rare autoimmune vesiculobullous disease. It clinically mimics dermatitis herpetiformis and has immunofluorescent findings typical of pemphigus. PH occurs in adults more commonly than children and is often effectively treated with dapsone. We report a case of PH occurring in a 9-year-old boy that was refractory to dapsone and to various other steroid-sparing medications but resolved with methotrexate.

Hereditary mucoepithelial dysplasia: unique histopathological findings in skin lesions.

Hereditary mucoepithelial dysplasia (HMD) is a rare, autosomal dominantly inherited, multisystem disease thought to be caused by abnormalities in desmosomes and gap junctions. HMD affects the skin, mucosae, hair, eyes and lungs. Nearly all patients clinically display the triad of non-scarring alopecia, well-demarcated mucosal erythema and erythematous intertriginous plaques. Although histopathological findings of mucous membrane epithelium have been well characterized, only three reports have described histopathologic findings in the skin. We report a case with unique histopathological findings not previously reported in HMD.

Azathioprine-induced EBV-positive mucocutaneous ulcer.

Epstein-Barr virus (EBV)-positive mucocutaneous ulcer was recently described as a clinicopathologic entity occurring secondary to iatrogenic or age-related immune suppression. The histopathology of EBV-positive mucocutaneous ulcer reveals a polymorphous infiltrate including atypical large B-cells and Reed-Sternberg-like cells which are CD20-positive, CD30-positive and EBV-positive. The disorder follows an indolent and self-limited course. We report a case of EBV-positive mucocutaneous ulcer secondary to prolonged use of azathioprine for the treatment of pemphigoid and highlight the need for recognition of this disorder by dermatopathologists and dermatologists.