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Dermatopathology: Practical & Conceptual April - June 1995
Searching for Diogenes: Bulge-Activation Hypothesis Part II—The Bulge is Not a Bulge
Cosimo Misciali, MD
A. Bernard Ackerman, MD
1927 Felix Pinkus
1951 Hermann Pinkus
1958 Hermann Pinkus
1961 Sanderson & Thiede
1987 Headington & Astle
1990 Leshin & White
1990 Cotsarelis, Sun, Lavker
1991 Sun, Cotsarelis, Lavker
1991 Lavker, Cotsarelis, Wei, Sun
1991 Lane, Wilson, Hughes, Leigh
1992 Jaworsky, Kligman, Murphy
1993 Yang, Lavker, Sun
1993 Lavker, Miller, Wilson, Costarelis, Wei, Yang, Sun
1993 Kobayashi, Rochat, Barrandon
1994 Rochat, Kobayashi, Barrandon
Entwicklungsgeschichte des Menschlichen Wollhaares. Anat Hefte Abt. 1904;XXIII:3-66 (
Fig. 5 [Fig. 14] Tangential view of a germinal cone, tip of the inner root sheath, m. arrector, sebaceous gland, outer root sheath, undifferentiated cells of the hair cone, bulge, glassy membrane, papilla. (Reproduced with permission.) Key: Tangentialschnitt eines Haarzapfens = secondary hair germ; Spitze der inneren Wurzelscheide = tip of inner root sheath; Talgdrüse = sebaceous glands; Äussere Wurzelscheide = outer root sheath; Indifferente Zellen des Haarkegels = hair cone; Wulst = bulge; Glashaut = vitreous membrane; Papille = papilla; M. arrector = arrector pili muscle
"The bulge" develops independent of any pull upon it of a musculus erector pili.
"The bulge" does not give rise to a new follicle. Its function is to facilitate retraction of a club hair during a follicular cycle.
The outgrowths that constitute "the bulge" are pathologic.
Stöhr denied that "the bulge" functions as the source of cells for a new follicle, but he did not propose an alternative explanation for the reservoir of them.
"The bulge" plays no role in the ascent of a club hair. A club hair comes to rest (telogen) at the base of the isthmus.
Bulges, i.e., protuberances of isthmic epithelium, contrary to the views of Unna and Stöhr, are normal, not pathologic.
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