Resolving Quandaries in Dermatology, Pathology & Dermatopathology

Origin of Adnexal Neoplasms?

…s its development as a bulge or collar at the junction of the infundibulum and isthmus of the hair follicle.” Weedon D. Skin Pathology. London: Churchill Livingstone, 2002. Implicit in the thinking of many general pathologists is the assumpti…

Histologic Diagnosis of Inflammatory Skin Diseases

Images

…tosis is virtually specific for pityriasis rubra pilaris. The infundibulum is dilated by a plug of ortho- and parakeratotic cells. Unlike the situation in psoriasis, the granular zone in pityriasis rubra pilaris is preserved and mounds of parakeratos…

Histologic Diagnosis of Inflammatory Skin Diseases

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…cial actinic ┬áThe cornoid lamella on the left springs from an infundibulum. Cornoid lamellae also may emanate from eccrine ducts or surface epidermis itself. The condition was named porokeratosis because Mibelli, who described it, believed that all c…

Resolving Quandaries in Dermatology, Pathology & Dermatopathology

Trichodiscoma Related to the Hair Disk and Merkel-Cell Neoplasm to Merkel Cells?

…cribed first by Felix Pinkus, emerge from the junction of the infundibulum and isthmus and, in sections cut vertically, are seen to hang as cords of undifferentiated epithelial cells along the sides of the follicle and parallel to it. Because those c…

Histologic Diagnosis of Inflammatory Skin Diseases

Infundibulitis secondary to agents topical

…mmatory process usually expresses itself as suppuration in an infundibulum. What distinguishes some suppurative infundibulitides induced by agents topical from suppurative infundibulitides brought about by other types of factors noninfectious is the…

Histologic Diagnosis of Inflammatory Skin Diseases

Granuloma faciale

…les, each producing a hair which emerges from an ostium of an infundibulum. Differential diagnosis histopathologic Erythema elevatum diutinum, for purposes practical, is identical with granuloma faciale, except for findings histologic that pertain to…

Resolving Quandaries in Dermatology, Pathology & Dermatopathology

Reactive Perforating Collagenosis?

…xuberant sufficiently, “perforate” the wall of an infundibulum, resulting in neutrophils and other infundibular contents being spewed into the dermis) complicated by the effects of rubbing and scratching. In summary, much that has been wr…

Histologic Diagnosis of Inflammatory Skin Diseases

Images

…kened bundles of collagen in the upper part of the dermis, an infundibulum plugged by corneocytes, a thinned surface epidermis, and compact orthokeratosis = Morphea, fully developed ┬áThe changes shown here are those of a superficial manifestation of…