Clinical and histopathologic spectrum of cutaneous Rosai-Dorfman disease in Taiwan

Cutaneous Rosai-Dorfman Disease

Cutaneous Rosai-Dorfman disease (CRDD) is a rare proliferative disorder of histiocytes with unknown etiology, broadly different from systemic Rosai-Dorfman disease. We present the largest series of CRDD, describing the clinical manifestation, histopathology, immunohistochemistry, and follow-up course of 25 cases in China. Clinically, 39 skin lesions in 25 patients were divided into 3 main types: papulonodular type (79.5%), indurated plaque type (12.8%), and tumor type (7.7%). Extremities were the most frequently involved, followed by trunk and face. None of the patients was found to have visceral organ involvement or lymphadenopathy. Microscopically, CRDD was characterized by scattering, clusters or sheets of large polygonal histiocytes intermingled with a florid, mixed inflammatory infiltrate. The most important feature was emperipolesis, which can be highlighted by S-100 protein stain. Patch and bandlike infiltrate of numerous mature plasma cells around glands and vessels was a constant finding in all lesions. Neutrophils existed in all cases to a variable degree with 2 cases forming microabscess. Four cases were remarkable for fibrosis, and xanthomatous change was observed in 2 cases. Coexistence of localized Langerhans cell histiocytosis and CRDD was interestingly found in case 7, which was evidenced by CD1a stain. Clinical follow-up in 22 patients, ranging from 2 to 55 months, indicated that surgical excision was the exclusive effective treatment for CRDD. Partial or complete spontaneous remission was achieved in 7 patients within 6 to 55 months. Owing to its favorable outcome, CRDD should be differentiated from a variety of benign and malignant lesions. Recognition of its wide clinical spectrum and histologic features combined with S-100 protein stain can help to establish the correct diagnosis.

Aggressive histiocytic disorders that can involve the skin

Histiocytoses are a heterogeneous group of disorders that are characterized by the proliferation and accumulation of reactive or neoplastic histiocytes. Three classes of histiocytoses have been defined: class I, Langerhans cell disease; class II, non-Langerhans cell histiocytic disease without features of malignancy; and class III, malignant histiocytic disorders. Although the disorders in classes I and II usually have a benign appearance on histology and are commonly non-aggressive and self-healing, some can cause debilitating or even fatal outcomes. Such cases beg the question: what stimulates aggressive behavior of a classically benign disease? New molecular information may now provide insight into the driving force behind many of the aggressive histiocytoses. In this article, we review Langerhans cell disease and seven aggressive histiocytoses that can involve skin, discuss histologic features that may forecast a poor prognosis, and discuss the molecular findings that help to explain the pathophysiology of these aggressive histiocytic disorders.

Cutaneous Rosai-Dorfman disease: clinicopathological profiles, spectrum and evolution of 21 lesions in six patients

BACKGROUND

An uncommon histiocytosis primarily involving the lymph nodes, Rosai-Dorfman disease (RDD, originally called sinus histiocytosis with massive lymphadenopathy) involves extranodal sites in 43% of cases; cutaneous RDD (C-RDD) is a rare form of RDD limited to the skin. The clinicopathological diagnosis of C-RDD may sometimes be difficult, with different clinical profiles from those of its nodal counterpart, and occasionally misleading histological pictures. There have been few multipatient studies of C-RDD and documentation of its histological spectrum is rare.

OBJECTIVES

To identify the clinical and histopathological profiles, associated features, and the chronological changes of this rare histiocytosis.

METHODS

From 1991 to 2002, patients diagnosed as having C-RDD were collected in four academic hospitals. Clinical presentations, treatments, and courses of each case were documented. In total, 21 biopsy specimens obtained from these patients were re-evaluated and scored microscopically with attention to the uncommon patterns and chronological evolution both clinically and histologically.

RESULTS

We examined six patients with C-RDD, three men and three women. The mean age at the first visit was 43.7 years. The clinical presentations were mostly papules, nodules and plaques, varying with the duration and depth of lesions. Although the anatomical distribution was wide, the face was most commonly involved. Evolutional changes were identified clinically, as the lesions typically began with papules or plaques and grew to form nodules with satellite lesions and resolved with fibrotic plaques before complete remission. No patient had lymphadenopathy or extracutaneous lesions during follow-up (mean 50.5 months). At the end of follow-up, the lesions in four patients had completely resolved irrespective of treatment; two patients had persistent lesions. The histopathological pattern of the main infiltrate, the components of cells and the stromal responses showed dynamic changes according to the duration of lesions. The characteristic Rosai-Dorfman cells (RD cells) were found in association with a nodular or diffuse infiltrate in 15 lesions (71%). Four lesions (19%) demonstrated a patchy/interstitial pattern. One lesion (5%) assumed the pattern of a suppurative granuloma. RD cells were less readily found in these atypical patterns. Conspicuous proliferation of histiocytes associated with RD cells was found in three lesions, including xanthoma, localized Langerhans cell histiocytosis and xanthogranuloma. Along with lymphocytes, plasma cells were present in all lesions, often in large numbers with occasional binucleated or trinucleated cells. Variably found in the lesions were neutrophils (nine lesions, 43%) and eosinophils (13 lesions, 62%). The former occasionally formed microabscesses, while the latter were often few in number. Vascular proliferation was a relatively constant feature (90%). Fibrosis was found in 10 lesions (48%).

CONCLUSIONS

Our study further confirms that C-RDD is a distinct entity with different age and possibly race distributions from RDD. Compared with its nodal counterpart, C-RDD demonstrates a wider histopathological spectrum with different clinicopathological phases depending on duration of the lesions. Awareness of these features is helpful in making a correct diagnosis. The associations of C-RDD with other histiocytoses may have important implications for the pathogenesis of this rare histiocytosis.