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The Spongiotic and Psoriasiform Disorders (S1C1 - Home)
(A presentation of patterns that are basic to an understanding of inflammatory diseases involving the reactive superficial unit of the skin)
Richard J. Reed, M.D., New Orleans, LA
You are at the first tier (HOME) of Section 2. This section, like all the sections, with the exception of Section 14, is arranged in three tiers (There is a dummy section, the SITE DIAGRAM, that also is in three
tiers; it serves as an introduction to the structure of each section and to the use of the navigation aids; a navigation bar linked to the SITE DIAGRAM is present in the mauve
cluster at the end of this page). The second tier of all the sections, with the exception of Section 14, is basically textual and is concerned with a discussion of reaction patterns. In the clusters
of navigation bars to the left, items identified with an S-C- are textual chapters; S-C-items additionally
identified with an “-X” are parent textual chapters; they relate in a spatial sequence to one or more pictorials at level 3. Each parent textual chapter is associated with a group of pictorials at the 3rd level. Pictorial items are identified by selecting items structured as “S-C-P-”, or as “S-C-VA-”. You can find access, if at textual level (2nd tier), to relevant pictorials by making a selection in the clusters of navigation bars in the MASTERBORDER on the left and clicking on your selection. The
blue first cluster of navigation bars provides access to the 1st level (HOME), and to all textual chapters at level 2. At level 2 and when viewing a parent
textual chapter, the blue cluster also provides access to the children (i.e., relevant pictorials) at level 3. A beige
second cluster in the MASTERBORDER provides access to parent textual chapters (identified with a suffix, “X-”) at level 2, and to respective pictorials at level 3.
A mauve cluster at the end of each page (chapter) of this section provides access to each of the other sections of this site. A cluster of two green navigation bars provides access to two web sites. In moving from the pictorials back to the textual chapters, the navigation
bar of the browser might also be useful, if you have just changed tiers (the movement in this case would be temporal rather than spatial). In Section 14, the second tier is devoted to pictorials; there is no third
tier. At the end of each page, a click on an “UP” button will take the reader up one tier; if at level III, the click will take the reader to the relevant parent page at tier 2. A click on the “Back”
button will take the reader back one page along the horizontal axis of the current tier (note: there is only one page on the first tier [HOME], and at level 3 only pictorials that are children of a particular parent
chapter at tier 2 will be available). The reader should be cautioned that the text of each chapter may be exhausted before the reader has reached the end of the page (chapter). In searching for appropriate
navigation bars, the reader should, in his search, follow the MASTERBORDER to its end. At the end of each page, there is one additional aid to navigation. This aid (“NEXT”
button) will take the reader, if he is at the second level, to the next page of text; if he is at the third (pictorial) level, a click on this bar will take the reader to the next page of pictorials (in sequence), with the stipulation that sequential movement using this aid is limited; only pictorials that are grouped in a fashion that is relevant to a single parent textual page will be accessible. All pages of text at the second level are identified as SECOND LEVEL at the end of the page. If there is no identification at the end of the page, and the reader is not HOME, then he is at the third level (additionally, and easily, recognized as the pictorial level simply by the presence of pictorials on the screen).
INTRODUCTION
The lesions of Section 2 are in part proliferative disorders affecting the epidermis, particularly a distinctive functional unit of the epidermis - the basal unit. For most examples, the proliferative changes are
associated with alterations in the fluidity of the epithelial interstitial matrix. The processes to be discussed are inflammatory diseases affecting a reactive unit of the skin - the reactive superficial unit (a
unit comprised of the epidermis
and the adventitial dermis; two anatomic compartments are combined to form the unit). The adventitial dermis is comprised of the papillary dermis, the adventitia of vessels, and the adventitia of the skin appendages. At the third tier of all the sections with the exception of Section 14, pictorials, as related to basic aspects of inflammatory diseases of the skin, provide a visual display of the effects of inflammation in a particular setting on the structure of the skin. For both the spongiotic and psoriasiform disorders, and the lichenoid disorders, the reactive superficial unit is primarily affected.
This presentation, in large part, is most basic; it may be of little interest to practicing pathologists. It was initiated as a teaching aid for students, residents, fellows, and pathologists at a time when
dermatopathologists were few in number. It still anticipates many of the problems encountered by neophytes in dermatopathology. I would hope that this presentation of basic morphology might accelerate a learning
process that otherwise is dependent on incremental presentations of specific lesions. The latter approach is based on an anticipation that senior residents, by having had repeated exposure to the histologic patterns
of individual lesions, eventually will have, in some manner, also assimilated basic concepts of pathology. This is an attempt to reverse the common approach and to present basic concepts as the cornerstone for an
understanding of specific and individual lesions.
In this Section (2), emphasis will be on disorders in the spongiotic and psoriasiform categories.
Each section will include an IMAGE MAP. By referring to the IMAGE MAP, it is possible to go directly to specific, individual pictorials. The IMAGE MAP will be the second chapter of each section (this being Section
2), but the first chapter of the second tier (hence, in each section, the IMAGE MAP is a part of Chapter 2). If the reader wishes to by-pass the textual components of the second tier, he can go to the IMAGE MAP and
then select specific pictorials. A brief description of the basic process accompanies the labels for individual pictorials or groups of pictorials. Once the reader, in his navigations, has reached the third tier,
the pictorials of each page are accessible in a sequence (but only in groups as defined by the relationship between groups of pictorials and parent textual pages on tier 2) by clicking on a “SEQUENCE” (“NEXT”)
navigation bar at the end of a page of pictorials.
In addition on the second tier of this section, a SECTION INDEX is included. It is the third chapter and is on the second tier for Sections 1, 8, & 15. For the other sections, the SECTION INDEX follows the IMAGE
MAP on page (chapter) 2. By referring to the SECTION INDEX, the reader can select specific sections and, in turn, specific topics; to access his selection, he should search out the appropriate navigation bar in the
mauve cluster at the end of each page.
Click on the appropriate navigation bar in the first (blue) cluster to the left to go to the IMAGE MAP or the SECTION MAP.
The aids to navigation include several clusters of navigation bars in the MASTER BORDER to the left, or at the end of each page. By moving along this border, the reader should find aids to navigation which will
provide access to selected text (textual chapters of the second tier of this section) and aids to navigation to selected pictorials of this section. If the reader wishes to go directly to the pictorials, a CLICK on the first S-C-P-, or first S-C-VA- item in the second beige
cluster in the MASTERBORDER to the left will take the reader to the first chapter (pictorial) of the third tier. Also, a click on each underlined item in any portion of text, such as the items of the IMAGE MAP, or on underlined items in a parent chapter at level 2, will provide access to the relevant pictorial.
There are two green
navigation bars (bweems.com and REED PATCH 3 [pathology-skin-rjreed.com/index.htm]) at the end of each page.The first bar identifies an external link to a site providing discussions of interesting cases, both inflammatory and neoplastic in nature.The second bar provides access to a site mostly devoted to melanocytic lesions.
The Reactive Superficial Unit of the Skin:
Cutaneous Epithelia and their Stroma
(epithelium and the adventitial dermis as a reactive unit)
The reactive superficial unit of the skin includes the epidermis and the papillary dermis; in some examples, the follicular epithelium, especially that of the infundibular portion and the perifollicular sheath also
are involved. In this characterization of an anatomic reactive unit, the vascular plexus plays an important role. Diseases involving the reactive superficial unit are the common inflammatory disorders. In defining
specific categories, there are at least two basic categories: 1.) the immunostimulatory processes that are spongiotic and psoriasiform, and 2.) the immunodestructive processes that are lichenoid. In the former
category, the basal unit of the epidermis is preserved and undergoes varying degrees of hyperplasia. In addition to basal unit hyperplasia, an alteration of the fluidity of the epidermal interstitial matrix is
variably represented; it is manifested in widening of spaces among keratinocytes of the basal epidermal unit; this response is generally characterized as spongiosis (inter-cellular edema). Basal unit hyperplasia
often results in elongation of rete ridges; this response generally is characterized as a psoriasiform pattern. Without an understanding of the proliferative, basal unit hyperplasias, it is difficult to come to an
understanding of the lesions in the category of the cytolytic disorders of the basal unit (lichenoid reactions in varied patterns).
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