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Chapter 82. Sarcoidosis

Definition

An inflammatory (granulomatous) process that involves, among other organs, the lungs, lymph nodes, and skin, and the latter in the form usually of papules, sometimes in arcuate and annular configuration, especially on a face, but also on the extremities, and often in pre-existing scars. In addition to papules, there may be subcutaneous nodules, hypopigmented patches, and ichthyosiform changes.

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Adjunctive Diagnostic Test

Chest x-ray is mandatory in order to recognize characteristic manifestations in the lungs, and x-ray of other organs, such as bones, may also be indicated. Calcium levels in the serum should be monitored for signs of hypercalcemia. Serum angiotensin-converting enzyme may be positive in extrathoracic sarcoidosis.

Course

Tiny papules of sarcoidosis tend to enlarge, but usually do not become nodules. Sometimes those papules are so numerous and set so closely that a plaque results; in other instances the papules may be arranged in an annulus. The papules of sarcoidosis tend to persist, as does the disease itself. New lesions may appear over the course of years, but, as a rule, old lesions do not disappear.

Integration: Unifying Concept

The gross features and changes histopathologic of sarcoidosis are distinctive in every organ in which the disease makes itself manifest. In the skin, papules consist of discrete collections of epithelioid histiocytes. Because those collections are devoid of encircling dense infiltrates of lymphocytes, they are referred to as “naked tubercles.” Plaques of subcutaneous sarcoidosis may involve the dermis in a manner just like that of papules, but, in addition, many granulomas are present within fat lobules and, to a much lesser extent, within septa.

Findings histopathologic like those of sarcoidosis in the skin are seen in lesions of sarcoidosis in organs such as lymph nodes, lung, eye, and bone. In short, sarcoidosis is a systemic granulomatous disease. Involvement of skin by sarcoidosis implies that other organs are also involved by the same pathologic process. The ichthyosiform changes of sarcoidosis usually occur on the legs in the region of the anterior tibiae and, being an expression of “acquired” ichthyosis, they exhibit histopathologic findings indistinguishable from those of ichthyosis vulgaris.

The cause of sarcoidosis is not known, but the histopathologic findings are most consonant with an infectious process.

Therapy

Click here for an up-to-date discussion of therapeutic management presented in Therapeutic Strategies in Dermatology.

Distribution

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Fig. 82-1

Papules on and around the nose.


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Fig. 82-2

Ring-like papules, some of them encircling an atrophic center.


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Fig. 82-3

Papules.


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Fig. 82-4

Dells that represent atrophic scars at sites of former papules of sarcoidosis.


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Fig. 82-5

Fusiform swelling of fingers (osteitis cystica).


Configuration

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Fig. 82-6

Annular lesions with a depressed center and a rim made up of tiny, shiny, smooth papules. Some papules are scaly.


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Fig. 82-7

Papules in and contiguous with a scar.


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Fig. 82-8

Papules contiguous with a scar.


Individual Lesions

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Fig. 82-9

Papules forming rings.


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Fig. 82-10

Atrophic macules surrounded by papules in a ring.


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Fig. 82-11

Plaques with scalloped border and atrophic center.


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Fig. 82-12

Atrophic hypopigmented nummular plaques.


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Fig. 82-13

Scaly hyperpigmented plaques.


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Fig. 82-14

Papules, some with crusts, on the alae nasae, nasolabial folds, and upper lip.


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Fig. 82-15

Smooth-surfaced and scaly papules and plaques.


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Fig. 82-16

Smooth-surfaced papules and plaques.


Lupus Pernio

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Fig. 82-17

Nodule on the nose and a plaque on the cheek (lupus pernio).


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Fig. 82-18

Nodule on the nose (lupus pernio).


New! Additional Images

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Fig. 82-19 A

Sarcoidosis: This patient with widespread lesions has scleritis and conjunctivitis in addition to slightly reddish-brown papules that are approximated closely but, nonetheless, remain mostly discrete; in some regions the papules have become confluent.


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Fig. 82-19 B

Sarcoidosis: This patient with widespread lesions has scleritis and conjunctivitis in addition to slightly reddish-brown papules that are approximated closely but, nonetheless, remain mostly discrete; in some regions the papules have become confluent.


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Fig. 82-20 A

Sarcoidosis: These smooth-surfaced, poorly circumscribed plaques are an unusual manifestation. The lesion shown close up has a slightly wrinkled surface, a sign of incipient atrophy.


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Fig. 82-20 B

Sarcoidosis: These smooth-surfaced, poorly circumscribed plaques are an unusual manifestation. The lesion shown close up has a slightly wrinkled surface, a sign of incipient atrophy.