Case 1 History
The patient is a 52-year-old male with a recent history of reddish brown follicular papules and nodules on the central face. The patient reports flushing on drinking alcohol or hot liquids. Telangiectasias are noted adjacent to the papules on examination.
Microscopic Findings
Sections show aggregates of epithelioid histiocytes in the upper half of the dermis surrounded by lymphocytes, adjacent to hair follicles, with foci of necrosis ( Fig. 5.1 ).
Diagnosis
Rosacea
Clinical Presentation
Rosacea (acne rosacea) has multiple clinical patterns, ranging from an erythematous indurated rash with telangiectases to red and red-brown follicular-based yellow-brown papules on the face. Some cases may present with a papulopustular appearance. A history of flushing or blushing with hot liquid, spicy foods, or alcohol is characteristic. Long-standing disease can result in rhinophyma. Of note, lupus miliaris disseminatus faciei is a severe form of granulomatous acne rosacea in which eyelid involvement is frequent.
Histopathology
The microscopic features of rosacea vary according to the clinical appearance. Erythematous, telangiectatic lesions show a variable perivascular and perifollicular lymphocytic, lymphohistiocytic, or lymphoplasmacytic inflammatory infiltrate with scattered telangiectases. Dermal edema may also be evident. With progression, folliculocentric lymphocytes and epithelioid histiocytes assemble and become more prominent together with perivascular lymphocytes and plasma cells. The vessels are thin walled and dilated (telangiectases).
Classic granulomatous involvement shows a prominent infiltrate of epithelioid histiocytes. There may be concurrent acneiform follicular change with infundibular plugging. Pustular rosacea includes a variable composition of intrafollicular and intracorneal neutrophils. Sebaceous gland hyperplasia and fibrosis are the secondary histopathologic correlates of rhinophyma, which stems from chronic persistent disease. Rosacea may hold a pathogenic link to Demodex because these organisms are frequently present on biopsy.
Differential Diagnosis
The differential diagnosis includes infections such as tuberculosis, tuberculoid leprosy, syphilis, and leishmaniasis ( Table 5.1 ).
| Acne Rosacea | Lupus Vulgaris | Tuberculoid Leprosy | Syphilis | |
|---|---|---|---|---|
| Causative agent | Multifactorial, with a vasoactive component; some cases are associated with Demodex folliculorum | Mycobacterium tuberculosis | Mycobacterium leprae | Treponema pallidum |
| Clinical features | Red-brown follicular pustules on the face | Red-brown papules | Hypopigmented anesthetic plaques | Disseminated papules and nodules |
| Distinctive histopathologic features | Perifollicular granulomas | Upper dermal granulomas with necrosis | Lower dermal granulomas with perineural involvement | Granulomas with plasma cells |
| Infiltrate | Lymphocytes and histiocytes | Epithelioid histiocytes | Epithelioid histiocytes | Lymphocytes, histiocytes, and plasma cells |
Perioral Dermatitis
Clinical Presentation
Perioral dermatitis presents as perioral erythematous follicular papules, often in females or children. Occasional examples also show a periocular distribution as well. A history of prior potent topical steroid use or application of cosmetics may be elicited in some cases. Many dermatologists consider perioral dermatitis to be a variant of rosacea.
Histopathology
The microscopic pattern is identical or highly similar to rosacea, and the disease centers on hair follicles. There may be follicular spongiosis coupled with folliculocentric lymphocytes, histiocytes, and occasional multinucleated giant cells. Dilated blood vessels are typically present, and there may be accompanying dermal edema.
Tuberculosis
The most common clinical variant of tuberculosis (lupus vulgaris) presents as reddish brown papules with an apple jelly color. Key histopathologic differences from rosacea include an absence of follicular involvement (the dermal arrangement may be random), necrosis, and the presence of acid-fast bacilli.
Clinical Presentation
Papules are often indurated and show apple jelly color on diascopy.
Histopathology
Sections show collections of epithelioid histiocytes in the upper half of the dermis with accompanying lymphocytes ( Fig. 5.2 ). There may be associated necrosis.
Tuberculoid Leprosy
The granulomas involve the lower dermis and extend around nerves and adnexa.
Clinical Presentation
Patients present with hypopigmented well-demarcated anesthetic plaques.
Histopathology
Histopathology reveals aggregates of epithelioid histiocytes surrounded by lymphocytes, particularly in the lower dermis ( Fig. 5.3 ). In addition, granulomas can be identified around small nerves, hair follicles, and sweat glands.
Granulomatous Secondary Syphilis
Clinical Presentation
Patients show indurated nodules and plaques of varying sizes.
Histopathology
Microscopy reveals aggregates of epithelioid histiocytes surrounded by lymphocytes and plasma cells, and this infiltrate typically involves the reticular dermis ( Fig. 5.4 ). In addition, granulomas can be identified around vessels with plump endothelium. The density of organisms can vary.
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Acne rosacea
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Clinical: red-brown follicular pustules and flushing
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Histopathology: perifollicular lymphocytes or granulomas associated with telangiectasia
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Tuberculosis or lupus vulgaris
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Clinical: papules with an apple jelly appearance
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Histopathology: superficial granulomas associated necrosis and acid-fast bacilli
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Tuberculoid leprosy
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Clinical: hypopigmented anesthetic plaques
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Histopathology: perineural and adnexal granulomas with rare acid-fast bacilli
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