Quiz 35: What is your diagnosis?

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Diagnosis: Quiz 35

Quiz 35

Answer: Sarcoidosis

Criteria for diagnosis clinically: A cluster of tan papules with a tinge of yellow, smooth-surfaced save for a solitary locus keratotic, and with a hypertrophic scar traversing much of the conglomerate, is that of sarcoidosis.

Differential diagnosis clinically: This could conceivably be a foreign body reaction and biopsy is crucial to excluding such a body. Because the surface of the lesion is smooth, the possibility of its having been caused by an agent infectious, such as a deep fungus or an atypical mycobacterium, is less likely.

Criteria for diagnosis histopathologically: Collections of epithelioid histiocytes surrounded by a patchy infiltrate of lymphocytes in loci throughout the dermis and a focally lichenoid lymphoplasmacytic infiltrate beneath a dell, ulcerated and covered by scale-crust, the latter being composed of parakeratotic cells, serum, and innumerable neutrophils, are those of sarcoidosis complicated by the effects of a previous surgical procedure.

Differential diagnosis histopathologically: This could be an infectious process, such as one brought into being by an atypical mycobacterium or a deep fungus, but the fact that the infiltrate around the collections of epithelioid histiocytes consists almost exclusively of lymphocytes rather than of lymphocytes and many plasma cells militates against that, as does the normal epidermis lateral to the crusted dell that is a result of the previous surgical procedure. No foreign body is apparent by direct examination or with the aid of polarized light.

Clinicopathologic correlation: The papule is constituted largely of the infiltrate of inflammatory cells, the characteristic hue is a result of a combination of factors, among those being the presence of epithelioid tubercles in conjunction with dilated venules filled with erythrocytes in the upper part of the dermis, and the locus keratotic seen clinically turns out histopathologically to be a bolus of scale-crust housed in a dell. The scale consists of cells parakeratotic and the crust of serum and neutrophils.

Options for therapy predicated on knowledge of histopathologic findings: As can be told from the photographs of the lesions clinical, an attempt was made previously to extirpate surgically lesions that proved to be those of sarcoidosis. The effort failed and new papules developed in and around the scar, a phenomenon not uncommon in sarcoidosis. Rather than undertake another attempt at remediation surgical, corticosteroids could be injected into the papules, those anti-inflammatory compounds being likely to shrink them.

1) The features clinical pose a challenge in diagnosis, especially in the context of a scar from a previous surgical procedure, it traversing much of the conglomeration somewhat longitudinal. A clinician new to this situation is compelled to query what, exactly, was biopsied previously and why new lesions appeared at the local site. On examination gross alone, no one answer seems tenable. The basic pathologic process could be infectious on one hand or sarcoidosis (assuming that that malady is not infectious) on the other. Even biopsy does not resolve the quandary; this tuberculoid granulomatous process could be either infectious or sarcoidosis.

2) Although sarcoidosis is said conventionally to be made up of "naked tubercles," i.e., collections of epithelioid histiocytes devoid of an enveloping mantle of lymphocytes and/or plasma cells, that, in reality, is not always the case. Episodically, the granulomas in cutaneous sarcoidosis are tuberculoid, that being true especially for granulomas situated mostly in the fat, i.e., "subcutaneous sarcoidosis." In this instance, the patient had indubitable sarcoidosis as evidenced by typical skin lesions elsewhere, but to this day there is no evidence of the disease being systemic overtly. On the basis solely of findings histopathologic, the possibility of sarcoidosis actually being infectious is gnawing to neurons.

3) The papules of sarcoidosis often are referred to as being "apple jelly" in hue. That orangish-yellow cast is a result directly and mostly of the collections of epithelioid histiocytes. The color distinctive, rather repeatable in fair-skinned persons, is shown to advantage better by use of diascopy.

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