Histologic Diagnosis of Inflammatory Skin Diseases

Hair Follicles

…le (catagen) when an appearance indistinguishable from that of isthmic epithelium is assumed by them. That epithelium, both of the isthmus and a follicle well advanced in catagen, is characterized by (1) a basal layer, (2) a spinous zone that is not…

Differential Diagnosis in Dermatopathology

Discussions

…pe have been called tricholemmal cysts, pilar cysts, sebaceous cysts, and wens. The lining of isthmus-catagen cysts is the same as that of the outer sheath at the isthmus (the uppermost part of a follicle) and of a follicle well advanced in catagen (…

Differential Diagnosis in Dermatopathology

Differential Diagnosis

Infundibular cyst Isthmus-catagen cyst 1. Cyst lining consists of stratified squamous epithelium that resembles normal infundibular epidermis, i.e., the cells flatten as they mature; the granular zone persists 1. Cyst lining consists of stratifi…

Differential Diagnosis in Dermatopathology

Infundibulo-folliculo-sebaceous cystic hamartoma vs. Steatocystoma

An inflammatory process that develops secondary to trauma, usually in the form of a penetrating injury or rupture of a follicle, and that proceeds through stages of granulation tissue with numerous extravasated erythrocytes, granulomatous inflammati…

Differential Diagnosis in Dermatopathology

Dilated pore vs. Pilar sheath acanthoma

An inflammatory process that develops secondary to trauma, usually in the form of a penetrating injury or rupture of a follicle, and that proceeds through stages of granulation tissue with numerous extravasated erythrocytes, granulomatous inflammati…

Histologic Diagnosis of Inflammatory Skin Diseases

Images

…10.3.3B: Lymphocytes obscuring papillae of follicles early in catagen + 10.3.3C + 10.3.3D = Alopecia areata ┬áThe absence of a well defined bulb that encloses largely a papilla is evidence of catagen, all of the follicles pictured being…

Differential Diagnosis in Dermatopathology

Differential Diagnosis

Infundibulo-folliculo-sebaceous cystic hamartoma Steatocystoma 1. Situated mostly in the dermis as a rule; sometimes also the subcutaneous fat 1. Situated in either the dermis or the subcutaneous fat, or both together 2. Cyst does not “p…

Resolving Quandaries in Dermatology, Pathology & Dermatopathology

Anagen Effluvium?

…hree months after the event that incited the follicle to enter catagen; when anagen begins anew, a new hair begins to be formed again. Telogen effluvium can be regarded as an all-or-nothing phenomenon: Either catagen is precipitated or there is no de…