Macules spread to the ears, neck and trunk

The answer is Benign cephalic histiocytosis. In 1971, Gianotti described a condition as, "Infantile histiocytosis with intracytoplasmic wormlike bodies."1 This description arose from such findings as the comma-shaped structures by ultrastructural studies (electron microscopy).1 It was later clear that many...

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The answer is Benign cephalic histiocytosis. In 1971, Gianotti described a condition as, “Infantile histiocytosis with intracytoplasmic wormlike bodies.”¹ This description arose from such findings as the comma-shaped structures by ultrastructural studies (electron microscopy).¹ It was later clear that many histiocyte disorders had similar ultrastructural findings, and the condition was renamed benign cephalic histiocytosis.

The histiocytoses are a group of proliferative disorders with a common progenitor cell in the bone marrow. The three histiocytes of cutaneous importance are the Langerhans cell, the mononuclear cell/macrophage and the dermal dendrocyte. The dysfunction of these cells leads to various disorders that are grouped into either Langerhans cell histiocytosis or non-Langerhans cell histiocytosis. Benign cephalic histiocytosis is a member of the non-Langerhans cell histiocytosis.

Only 40 cases of benign cephalic histiocytosis have been documented to date.¹ The disorder usually involves the head and neck, with an average age of onset of 15 months to 3 years. Approximatly 45% of the cases occur in children younger than age 6 months.²

There has been one report of an adult case in which the patient had T-cell lymphoma and the lesions were thought to be very similar to those found in benign cephalic histiocytosis. Overall, the disease is not gender-specific.^1,2

The cause of benign cephalic histiocytosis is not yet known. Researchers have started to pinpoint the pathogenesis using the given similarities in histopathology, immunohistochemical profile and ultrastructural appearance to those of juvenile xanthogranuloma (JXG) and generalized eruptive histiocytoma. Some authors and researchers suspect benign cephalic histiocytosis to be a variant of the former disorders.

A research study compared cases of generalized eruptive histiocytosis, benign cephalic histiocytosis and JXG histopathologically.^1,3 The conditions were so similar that investigators recommended they be classified as a single disease with a spectrum of clinical features.⁴

Clinically, benign cephalic histiocytosis is characterized by red to red-brown macules and papules that range from 2 to 5 mm in diameter. The papules usually are first noticed on the face; they also may be found on the ears and neck later in the course of the disease.⁵ On occasion, papules may be seen on trunk, arms, and thighs. This is uncommon and is only appreciated when benign cephalic histiocytosis reaches advanced stages.

The lesions may coalesce together in a reticular pattern.⁶ As time progresses, the papules will flatten and become hyperpigmented. The papules and macules will resolve spontaneously, but this may take months to years for some patients. The lesions are asymptomatic, and the course of the disease can be marked by exacerbations.

There is usually no mucosal membrane or systemic involvement. However, there has been one reported case of a young woman with benign cephalic histiocytosis who also developed diabetes insipidus.⁷

If unsure, a biopsy can definitively diagnose the patient. Benign cephalic histiocytosis has three histologic patterns: a lichenoid pattern, a diffuse pattern and a papillary dermal pattern.^1,8

In the lichenoid pattern, occasional lymphocytes are seen along with small regular histiocytes located perivascularly and within the superficial dermis. In the diffuse pattern, histiocytes are found throughout the dermis.

These histiocytes are usually round and regular, with minimal cytoplasm and no pleomorphic features. In contrast, pleomorphic histiocytes with abundant eosinophilic cytoplasm, hyperchromatic and sometimes indented nuclei and large nucleoli are a characteristic feature of the papillary dermal pattern.¹

This is the most common pattern and the infiltrate is often well-defined and closely approximated to the epidermis. Touton giant cells are absent in this all three patterns.

Electron microscopy studies may reveal classic cells with intracytoplasmic comma-shaped or wormlike bodies. However, such bodies are also found in many other disorders, such as Langerhans cell histiocytosis, JXG, generalized eruptive histiocytoma and Rosai-Dorfman disease.^1,9

JXG is by far the most difficult disorder to differentiate from benign cephalic histiocytosis. Found mostly in children, JXG is a benign, asymptomatic, and self-healing disorder. In comparison with benign cephalic histiocytosis, the lesions of JXG tend to be larger and are often classified as nodules rather than macules and papules. Also, JXG lesions are often found as either one or several individual nodules or are widespread and numerous.

Benign cephalic histiocytosis is generally a self-limited disorder without any complications, and treatment is not necessary. The individual lesions will heal spontaneously, leaving behind flat or atrophic hyperpigmented scars. Over time, these too will fade away. Nevertheless, follow-up is recommended since exacerbations of the disease and diabetes insipidus have been known to occur.^5,7

The parent and patient in this case were given extensive education and anticipatory guidance regarding the benign nature of this disorder. At the last follow-up appointment, some of the lesions had resolved, and the patient’s course had not been complicated by any exacerbations or the development of diabetes insipidus.

Kerri Robbins, MD is a resident in the department of dermatology at Baylor College of Medicine in Houston. The author has no relationships to disclose relating to the content of this article.

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References

1. JL Bolognia, JL Jorizzo, RP Rapini, eds. Dermatology, 2nd ed., St. Louis, Mo.: Elsevier-Mosby; 2008:1400-1401.

2. Jih DM, Salcedo SL, Jaworsky C. Benign cephalic histiocytosis: a case report and review. J Am Acad Dermatol. 2002;47:908-913.

3. Zelger BG, Zelger B, Steiner H, Mikuz G. Solitary giant xanthogranuloma and benign cephalic histiocytosis—variants of juvenile xanthogranuloma. Br J Dermatol. 1995;133:598-604.

4. Gianotti F, Alessi E, Caputo R. Benign cephalic histiocytosis: a distinct entity or a part of a wide spectrum of histiocytic proliferative disorders of children? Am J Dermatopathol. 1993;15:315-319.

5. Paller AS, Mancini AJ. Hurwitz Clinical Pediatric Dermatology, 3rd ed. Philadelphia, Pa.: Elsevier Saunders; 2006:251-252.

6. Peña-Penabad C, Unamuno P, Garcia-Silva J, et al. Benign cephalic histio­cytosis: case report and literature review. Pediatr Dermatol. 1994;11:164-167.

7. Weston WL, Travers SH, Mierau GW, et al. Benign cephalic histiocytosis with diabetes insipidus. Pediatr Dermatol. 2000;17:296-298.

8. DE Elder, R Elenitsas, BL Johnson, GF Murphy, X Xu, eds. Lever’s Histopathology of the Skin. 10th ed., Philadelphia, Pa.: Lippincott Williams & Wilkins; 2009:677-678.

9. RP Rapini. Practical Dermatopathology. Philadelphia, Pa.: Elsevier-Mosby; 2005:111.