Histologic Diagnosis of Inflammatory Skin Diseases

Blood Vessels

Blood vessels in the skin of an embryo come into being when mesenchymal cells arranged in an intricate network arborize and encircle conduits that are seen through a microscope as mere spaces. The dermal vasculature consists of a superficial and a d…

Differential Diagnosis in Dermatopathology

Discussions

Tuberculoid leprosy and sarcoidosis are granulomatous dermatitides that resemble one another histopathologically because both consist of aggregations of epithelioid histiocytes in the dermis and, sometimes, in the subcutaneous fat. Despite the simil…

Histologic Diagnosis of Inflammatory Skin Diseases

Confusing Terms (to be Avoided Scrupulously)

APOPTOSIS [Gk. apo- (away from) + ptosis (a falling)]: Reputed to be a specific type of cell death in which dead cells are said to undergo fragmentation by implosion with subsequent phagocytosis of nuclear debris (Fig. 3.40). The process is claimed…

Histologic Diagnosis of Inflammatory Skin Diseases

Subcutaneous Fat

The subcutaneous fat, like the dermis, is derived embryologically from mesenchyme. Primitive mesenchymal cells give rise to fibrocytes and to adipocytes. An adipocyte synthesizes so much fat in its cytoplasm that the lipid displaces and flattens the…

Dermatology Practical & Conceptual

A keratoacanthoma with venous invasion

Abstract Keratoacanthomas are variously regarded as a self-limiting variant of squamous cell carcinoma or as a distinct benign lesion and they very seldom show attributes normally associated with malignant behaviour, such as perineural invasion. Her…

Histologic Diagnosis of Inflammatory Skin Diseases

Dermoepithelial Interface

The basement membrane was defined first by conventional microscopy as a thin band situated immediately beneath basal keratocytes, a strip that was stained magenta by the periodic acid-Schiff method (Fig. 1.70). In time, with the aid of electron micr…

Resolving Quandaries in Dermatology, Pathology & Dermatopathology

Origin of Adnexal Neoplasms?

“Thus one needs to bear in mind the information required of a pathologist about a particular tumour, which can be summarized as follows: 1. What is the origin of the tumour? 2. What is likely the behavior of the tumour? 3. What is the extent…

Histologic Diagnosis of Inflammatory Skin Diseases

Images

Images 10.37.1A: Pustular dermatitis, infundibular + 10.37.1B: Numerous Demodex folliculorum and squames in a zone of suppuration = Suppurative infundibulitis of unknown cause Demodex, Pityrosporum, bacteria, sebum, squames, and cornified…

Resolving Quandaries in Dermatology, Pathology & Dermatopathology

Eccrine Neoplasms?

Classification of Skin Appendage Tumors Eccrine Differentiation Eccrine nevus Eccrine duct proliferation Eccrine-centered nevus Eccrine angiomatous hamartoma Syringofibroadenoma or acrosyringeal nevus Comedo nevus of the palm, linear eccrine nevu…