Benign cephalic histiocytosis.

A one and a half year old girl born of a non-consanguineous marriage presented with multiple asymptomatic erythematous to hyperpigmented and skin colored papules on both cheeks slowly increasing in number of 1 year duration. On the basis of clinical, histopathological, and immunohistochemistry findings, a diagnosis of benign cephalic histiocytosis was made.

INTRODUCTION

Benign cephalic histiocytosis (BCH) is a rare self-limiting non-Langerhan's histiocytosis that typically starts at the end of first year of life.[1] It was first described by Gianotti et al. in 1971.[2] Here we report such a rare case of BCH.

CASE REPORT

A one and a half year old girl born of a non-consanguineous marriage presented with multiple asymptomatic raised lesions on both cheeks of 1 year duration. The lesions were slowly increasing in number.

Dermatological examination revealed multiple erythematous to hyperpigmented and skin colored papules limited to both cheeks [Figure 1]. General examination and systemic examination were within normal limits. Physical and mental development were adequate for her age.

Figure 1

Multiple erythematous to hyperpigmented and skin colored papules limited to both cheeks

Routine investigations including serum cholesterol and triglycerides were within normal limits.

Differential diagnosis considered were BCH, juvenile xanthogranuloma, and angiofibroma. Skin biopsy from one of the papules showed a normal epidermis and sheets of foamy macrophages, a few histiocytes, and occasional eosinophils in the dermis [Figure 2 and 3]. Immunohistochemistry of the biopsy specimen showed CD68 (macrophage marker) positivity and CD 1a (Langerhan's cell marker) negativity [Figures 4 and 5]. Correlating the clinical, histopathological, and immunohistochemistry findings, a final diagnosis of BCH was made.

Figure 2

Section shows H and E stained slides (low power) showing sheets of foamy macrophages, a few histiocytes, and occasional eosinophils in the dermis

Figure 3

Section shows H and E, ×40 stained slides (high power) showing sheets of foamy macrophages, a few histiocytes, and occasional eosinophils in the dermis

Figure 4

CD 68 positive cells

Figure 5

The same cells are CD1a negative. Internal control has worked. It highlights the normal Langerhan's cells

DISCUSSION

BCH otherwise known as papular histiocytosis of the head is characterized by an asymptomatic eruption of papules on the head and neck of infants and young children, which subsequently spontaneously regresses leaving atrophic pigmented macules.[2] BCH typically presents as multiple small yellow to red brown papules primarily on the cheeks and forehead. Systemic involvement in the form of diabetes insipidus has been reported, but is extremely uncommon.[3] Biochemical and radiologic studies of patients with BCH have shown no consistent abnormalities. Physical and mental development of the children have been normal.[4]

The clinical differential diagnosis includes plane warts, multiple Spitz nevi, juvenile xanthogranuloma, Langerhan's cell histiocytosis, urticaria pigmentosa, generalized eruptive histiocytosis, and lichenoid sarcoidosis. All of them can be differentiated by histopathology or immunohistochemistry studies.[2] S-100 and CD 1a staining will differentiate Langerhan's cell histiocytosis.[2]

The histopathologic features of early lesions include a circumscribed infiltrate in the superficial dermis that consists predominantly of histiocytosis with occasional lymphocytes and eosinophils. Older lesions show a few giant cells with peripherally arranged nuclei and lymphocytes.[4] Electron microscopy shows that 5–30% of infiltrating cells have cytoplasm rich in comma-shaped bodies and coated vesicles.[5] Dense bodies may be present, and worm-like bodies have been described.[4]

Since the condition is self-limiting, no therapy is indicated. Forty two cases are reported in the literature so far;[6] of which only 12 cases had lesions confined to the face.[2] Thus, BCH is very rare, and cases limited to the face are even rarer. To the best of our knowledge and after thorough literature search, this is the first case of this kind reported from India.