Page 136 - The Netter Collection of Medical Illustrations - Integumentary System_ Volume 4 ( PDFDrive )

Plate 4-51 Integumentary System

NECROBIOTIC
XANTHOGRANULOMA

Necrobiotic xanthogranuloma is a rare skin condition
that is frequently associated with an underlying mono-
clonal gammopathy. It was first described in the early
1980s. Since then, many cases have been reported that
have confirmed this to be a distinct, albeit unusual and
infrequently encountered, skin condition. The patho-
logical findings of necrobiotic xanthogranuloma are
distinctive and are required to make the diagnosis.
Patients with this diagnosis need to be monitored rou-
tinely to watch for the development of a monoclonal
gammopathy and the possibility of multiple myeloma.
Clinical Findings: So few cases of necrobiotic xan-
thogranuloma have been reported that no firm conclu-
sion can be made on the epidemiology of the disease.
However, it is a disease of older adulthood, with almost
all cases occurring after the age of 50 years. The lesions
have been reported to occur anywhere on the human
body, but they are found most often on the forehead,
cheeks, and temporal regions around the eyes. The
periorbital region is almost always affected. Necrobi-
otic xanthogranulomas are typically yellowish to red
papules and plaques. There may be intervening atrophy
between the areas of involvement. The leading edge of
the plaques may have a red or violaceous hue. Occasion-
ally, nodules form. Secondary ulceration is frequently Patches and plaques on the face. Necrobiotic xanthogranuloma
reported, as are telangiectases and dilated dermal is most frequently encountered in a periocular location.
vessels, which are most prominent in the regions of
atrophy. The ulcerations take an extended period to
resolve. Most patients are distraught by the appearance
of the rash and complain of a mild pruritus, although
many have no symptoms. The clinical differential
diagnosis includes forms of planar xanthomas. A skin
biopsy helps differentiate these conditions. This disease
progresses over time and typically does not spontane-
ously remit.
Patients almost always complain of dry eyes or have
objective findings of proptosis. In rare cases, necrobi-
otic xanthogranuloma affects the lacrimal gland and
retrobulbar fat tissue.
Necrobiotic xanthogranuloma is associated with an
immunoglobulin G-κ (IgG:κ) monoclonal gammopa-
thy in most cases. The presence of a gammopathy
should make the clinician seek the advice of a hematolo-
gist to perform a bone marrow biopsy to help evaluate Low power. Diffuse dermal granulomatous infiltrate
for multiple myeloma. A small percentage of patients with giant cells
with this gammopathy have or will develop multiple
myeloma. Other frequently abnormal laboratory tests
in necrobiotic xanthogranuloma include an elevated
erythrocyte sedimentation rate (ESR), a decreased level High power. The giant cells can
of complement C4, and leukopenia. Many other abnor- be best appreciated on higher-
malities have been described, providing more evidence power microscopy. The giant
that this is a systemic disease and not an isolated skin cells are predominantly the
disease. Lesions of necrobiotic xanthogranuloma have Touton type.
also been described to occur in the upper respiratory
system and in the heart.
Pathogenesis: The pathogenesis has been theorized
to be an antibody response to a self-antigen, most likely unique and characteristic finding, when seen, is that of condition, so only anecdotal therapies have been
a form of lipid. This is unproven, and the exact etiology cholesterol-filled, needle-shaped clefts within the gran- reported. Topical and oral steroids have been somewhat
is unknown. ulomatous infiltrate. Giant cells, both the foreign body successful. Chemotherapeutic agents have been used
Histology: The biopsy findings of necrobiotic xan- type and the Touton type, are commonly seen. The with variable success, including the alkylating agents.
thogranuloma are unique and characteristic. A punch granulomatous infiltrate surrounds and envelops necro- Results have been varied, with some patients experienc-
biopsy or excisional biopsy should be performed to biotic collagen tissue. There is usually an underlying, ing long-term remission. Patients all need to be
allow for adequate evaluation. On first glance, the predominantly lobular panniculitis without vasculitis. screened for gammopathy and for the development of
entire dermis is filled with inflammatory cells. The Treatment: Therapy is difficult. No randomized pro- multiple myeloma. The presence of myeloma portends
inflammation is in the granulomatous category. A spective studies have been performed on this rare a worse prognosis.

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