Quiz 61
Answer: Suppurative infundibulitis
of undetermined cause
Criteria for diagnosis
clinically: Discrete, roundish
papules made up mostly of a central, caramel-colored scale-crust,
with a hint of rust, but also of an elevated, smooth-surfaced, pink
rim are those of a suppurative infundibulitis, the cause of which
is not apparent from inspection gross
alone.
Differential diagnosis clinically: The lesions
fulfill criteria for Kyrle's disease, known originally as
"hyperkeratosis follicularis et parafollicularis penetrans," which
fundamentally is a suppurative infundibulitis to which infundibular
hyperkeratosis in time becomes added.
Criteria for diagnosis
histopathologically: Infundibula
thinned markedly and widened dramatically by plugs of cornified
cells joined by countless neutrophils, those polymorphs also
present in large number in the interstitium of the upper half of
the dermis, are findings of a suppurative infundibulitis
accompanied by striking infundibular
hyperkeratosis.
Differential diagnosis histopathologically: The
changes pictured are just like those referred to as "perforating
folliculitis" as occurs in patients suffering from chronic renal
failure and who often are on hemodialysis. That process simply is
suppurative infundibulitis that comes to be affiliated with
infundibular hyperkeratosis.
Clinicopathologic
correlation: The scale is composed
of cornified cells and the crust of neutrophils; the caramel color
with a tint of rust is the result of the effects combined of
suppuration in the epidermis and hemorrhage in the uppermost part
of the dermis and in the lower part of the scale-crust; and the rim
is elevated by edema in dermal papillae and it is pink because
capillaries there are dilated greatly, they, in
vivo, having been filled with
erythrocytes.
Options
for therapy predicated on knowledge of histopathologic
findings: Treatment must be directed at the
cause presumptive of the suppurative infundibulitis and, in this
instance, none could be identified. Because dapsone administered
systemically has a muting effect on ingress of neutrophils, it
deserves of a
try.
1)
The term "suppurative infundibulitis" is descriptive of a pattern
histopathologic in skin, i.e., suffusion of epidermal infundibula
by myriad neutrophils. Those polymorphonuclear leukocytes emerge
from venules and capillaries of the superficial plexus and proceed
directly to infundibula. Soon, infundibular canals are so laden
with neutrophils that the epithelial lining becomes so thin that it
ruptures, the mass of neutrophils then being spewed into the dermis
where it tends to follow paths in the interstitium. Those stages in
the evolution of suppurative infundibulitis are evident in this
section of
tissue.
2) Every textbook of dermatology, general pathology, and
dermatopathology designates the findings histopathologic shown here
"suppurative folliculitis" or a variation on that theme, such as
"perforating folliculitis." In fact, as is apparent, only the
epidermis, in particular, the infundibular part of it, is affected
by the process. It is incorrect to characterize those changes as
ones of folliculitis when they truly represent an "epidermitis"
("infundibulitis"). The hair follicle consists of a bulb, stem, and
isthmus; in continuity with the isthmus is infundibular epidermis
that merges imperceptibly with surface epidermis. In short,
distinct differences histologic enable a follicle to be
distinguished readily from epidermis.
3)
Although on grounds morphologic, e.g., clinical and
histopathologic, the findings depicted in these photomicrographs
can rightly be termed "suppurative infundibulitis," it must be
understood that that diagnosis is descriptive of a process, not
specific for a disease established clearly. In brief, the term
"suppurative infundibulitis" characterizes a particular pattern
histopathologic, but it does not convey anything about whether the
cause of it is infectious or noninfectious and, if the latter,
whether of acne vulgaris, rosacea, pyoderma gangrenosum, Behçet's
disease, or idiopathic, to mention but some possibilities. Kyrle's
original patients with suppurative infundibulitis, as deemed by him
to have "hyperkeratosis follicularis et parafollicularis in cutem
penetrans," were diabetics, but identical changes morphologic
develop not uncommonly in persons on dialysis consequent to chronic
renal failure and on the thighs and legs of men who work beneath
hoisted cars and whose dungarees are drenched with machine oils.
The inducers of suppurative infundibulitis are many and diverse,
from agents occlusive to those responsible for inflammatory bowel
disease.
4)
Because the countless neutrophils in suppurative infundibulitis
manufacture products intensely pruritogenic often to nerve endings
in the uppermost part of the dermis, it is no wonder that many a
patient, such as one on hemodialysis, rubs vigorously and sometimes
scratches excitedly the "primary" lesions, inducing thereby
secondary changes of prurigo nodularis or of picker's nodule. Those
alterations are evident in features clinical and findings
histopathologic that complicate the initial suppurative
infundibulitis.
5)
Suppurative infundibulitis is analogous to many other distinctive
patterns formed by inflammatory processes in skin and subcutaneous
fat, among those being urticaria, leukocytoclastic vasculitis,
erythema multiforme, pyoderma gangrenosum, erythema nodosum,
nodular vasculitis, and even conditions as dissimilar as granuloma
annulare and psoriasis. Each of those entities can be identified
for what they are morphologically by dint of their singular
characteristic pattern, each of them having more than a single
cause which, in many instances, is not identifiable either by
inspection gross or examination microscopic.