Differential Diagnosis in Dermatopathology

Trichoadenoma vs. Microcystic adnexal carcinoma

A malignant neoplasm of melanocytes that, in the skin, begins as a macule and may become a patch or a papule. A flat lesion of melanoma tends to be asymmetrical, poorly circumscribed with a scalloped, jagged, or notched border, and variegate, mostly…

Differential Diagnosis in Dermatopathology

Discussions

Both sebaceous hyperplasia and nevus sebaceus of Jadassohn consist of abnormalities of sebaceous glands but the former, as the name denotes, is a hyperplasia, whereas the latter is a hamartoma that involves not only sebaceous units, but other adnexa…

Differential Diagnosis in Dermatopathology

Trichoblastoma, small nodular type vs. Trichoblastoma, large nodular type

A malignant neoplasm of melanocytes that, in the skin, begins as a macule and may become a patch or a papule. A flat lesion of melanoma tends to be asymmetrical, poorly circumscribed with a scalloped, jagged, or notched border, and variegate, mostly…

Resolving Quandaries in Dermatology, Pathology & Dermatopathology

Blaschkitis?

“Blaschkite de l’adulte is considered a new disease entity . . . described by Grosshans and Marot in their report of relapsing acquired unilateral skin lesions following Blaschko’s lines.” Megahed et al. Acquired relapsing…

Resolving Quandaries in Dermatology, Pathology & Dermatopathology

Blue Nevus?

“Two forms [of blue nevus] exist, the rare being termed ‘cellular blue naevus.’ In the common variety bipolar and dendritic melanocytes lie singly or in masses in the dermis. . . . The cellular type is composed of the same element…

Histologic Diagnosis of Inflammatory Skin Diseases

Definition of Inflammation in Historical Perspective

The word “inflammation” was introduced about 2,000 years ago by Celsus in one of the eight volumes he devoted to the history of medicine. In the third volume of that monumental work, Celsus mentioned four signs and symptoms he deemed to…

Histologic Diagnosis of Inflammatory Skin Diseases

Study By Disease

“Blue nevus” (Jadassohn-Tièche) (Quiz #360) “Blue nevus” (Jadassohn-Tièche) (Quiz #525) “Blue nevus” (Masson’s blue neuronevus) (Quiz #359) “Collagenous” nevus, papillary dermal type* (Quiz #11…

Resolving Quandaries in Dermatology, Pathology & Dermatopathology

Verruciform Xanthoma?

“A relationship most likely exists between the verruciform appearance of the epithelium and the underlying foam cells. . . . One might suspect that epithelial breakdown, from some as yet unknown cause may secondarily elicit a foam-cell respo…

Resolving Quandaries in Dermatology, Pathology & Dermatopathology

Eccrine Neoplasms?

…o., 1993:874. Tumors of cutaneous appendages Eccrine tumors Hamartomas and benign tumors Eccrine hamartomas Eccrine hidrocystoma Papillary eccrine adenoma Syrigoma Eccrine mixed tumor Cylindroma Spiradenoma Poroma group Eccrine poroma Dermal duct…