Jonathan D. Ho

Mimickers of classic acantholytic diseases

Acantholysis is a commonly encountered histological pattern which typically generates a differential of the pemphigus variants, Hailey–Hailey, Dariers and Grovers diseases. In addition to these diseases, the dermatologist and dermatopathologist must be aware of entities that mimic classic acantholytic dermatoses and of rare disease variants, which are characterized by acantholysis.

Folliculosebaceous neoplasms: A review of clinical and histological features

Numerous benign and occasionally malignant tumors arise from the folliculosebaceous apparatus. Confusing terminology, rarity of malignant variants and overlapping histological features can lead to diagnostic uncertainty. This review highlights the clinical and histopathological features that help to classify these entities, as well as the various syndromes associated with certain members of this large family of tumors.

Linearized solar elastosis of the legs: A novel presentation and review of the literature

There exists a spectrum of solar elastotic variants based on the clinical and histopathologic findings. We present here a peculiar case of solar elastosis that is unusual in its anatomic location, relative lack of background actinic damage, and pattern of linearization. Its presentation suggests that other factors in addition to ultraviolet radiation may play a role in the pathogenesis of solar elastosis.

Bullous complex regional pain syndrome: A description of the clinical and histopathologic features

Complex regional pain syndrome (CRPS, formerly reflex sympathetic dystrophy) is a poorly understood syndrome occurring most commonly after peripheral trauma.(1) Diagnostic features include pain, autonomic dysregulation, sensory/motor abnormalities and trophic changes involving the affected limb.(1,2) Dermatologic findings include erythema, atrophy, xerosis, erosive disease, and reticulated erythematous patches.(3,4) Exceptionally, blistering has been reported.(5-7) Given its rarity, the clinical and histopathologic findings of bullous CRPS are not well described. We report a case of bullous CRPS in a patient with mycosis fungoides (MF), describing the clinical and histopathologic features of this uncommon entity.

Amelanotic melanoma arising within a lesion of disseminated superficial actinic porokeratosis: An unusual presentation leading to a novel therapeutic approach

Disseminated superficial actinic porokeratosis (DSAP) is the most common variant of porokeratosis with a potential for malignant transformation. Its association with malignant melanoma, however, is exceedingly rare. Treatment of DSAP is often ineffective. We report a unique case of amelanotic melanoma arising within a lesion of DSAP. The melanoma was managed surgically, and her DSAP were treated successfully with a novel approach utilizing 5‐fluorouracil chemowraps.

Hairless lesion on the scalp

A 33-year-old Brazilian woman presented for evaluation of an asymptomatic, hairless lesion on her scalp, which had been present since birth. The patient reported that there had been no fluctuation in lesion size, and no drainage of purulent or keratinaceous material. She had no history of ocular or neurological disease. Previous investigations included a computed tomography scan, on which the lesion had an appearance suggestive of a cystic lesion without an intracranial connection, but was otherwise normal. Physical examination revealed the lesion to be a soft, smooth, alopecic, yellow plaque at the vertex of the scalp (Fig. 1). No other abnormalities were found. A biopsy was taken from the lesion.

Benign and malignant hybrid adnexal tumors in a patient with epidermodysplasia verruciformis

Epidermodysplasia verruciformis (EV) is a genodermatosis characterized by overgrowth of flat warts, pityriasis versicolor‐like lesions and an increased propensity for developing cutaneous squamous cell carcinomas due to abnormal susceptibility to infection with beta‐human papilloma viruses. Adnexal tumors are not typically associated with EV. Here we report a spectrum of hybrid adnexal tumors with divergent eccrine and folliculosebaceous differentiation, and cytologic features ranging from benign to frankly atypical, in a patient with inherited EV.