Pediatric Dermatology Vol. 14 No. 2 98-102, 1997 Nonlipidized Juvenile Xanthogranuloma: A Histologic and Immunohistochemical Study Cathy C. Newman, M.D.,* Sharon S. Raimer, M.D.,*t and Ramon L. Sanchez, M.D.*:!: Departments of *Dermatolog\, ^Pediatrics, and tPathology, University of Texas Medical Branch, Galve.'ston, Texas Abstract: Among all patients with a pathologic diagnosis of juveniie xanthogranuloma (JXG) seen at our institution from 19B3 to 1994, we identified five patients with an unusual histologic pattern that differed from the classic juvenile xanthogranuioma (CJXG) with foamy ceils and Touton giant cells. Four of these five cases, which we termed nonlipidized juvenile xanthogranuloma (NJXG), were seen in infants. The histoiogic features include a monomorphic infiitrate with absent or few foam celis and Touton giant cells. There is little inflammation, and mitotic figures are easily found. Four cases exhibit a diffuse sheetiike pattern while one is trabecuiar. immunoperoxidase staining was done. Aii iesions are con- sistently positive for factor Xilla as opposed to oniy focaily positive or negative in CJXG and negative in Langerhans cell histiocytosis (LCH). The S-100 was negative. NJXG represents an atypical histologic variant of JXG, which may suggest a malignant or aggressive tumor. The foliow- up, however, indicates that these lesions behave in a fashion simiiar to those of CJXG. The differentiai diagnosis shouid be made with LCH, intradermai nevus, and reticulohistiocytosis. The immunoperoxidase find- ings help to differentiate NJXG from these entities. Juvenile xanthogranuloma (JXG) is a benign disorder characterized clinically by the presence of one or several red to yellow skin nodules, predominantly seen in infancy and childhood. The histologic findings in mature lesions are characterized by a mixed infiltrate containing foam cells, foreign-body type giant cells, Touton giant cells, histocytes, lymphocytes, and eosinophils. We collected five ca,ses of a variant of JXG, which is seen mainly in infants and is characterized histologically by a monomor- phic infiltrate of histocytes without lipidization or giant cells and with very scanty inflammatory' infiltrate, if any. This variant, which we designated a.s nonlipidized juve- nile xanthogranuloma (NJXG), can be difficult to recog- nize and is occasionally confused with a malignant tumor, particularly since abundant mitosis may be seen. MATERIALS AND METHODS Five cases of NJXG from the files of the Departments of Pathology and Dermatology at the University of Texas Medical Branch were reviewed. Four ofthe patients were infants less than 1 year old. The solitary lesions were located on the face or trunk (Fig. 1). Table 1 summarizes the clinical data. Six additional cases of classic juvenile xanthogranuloma (CJXG) and two cases of Langerhans cells histiocytosis (LCH) were used as controls. The he- Address correspondence to Ramon L. Sanchez, M.D , Depart- ment of Dennatology, 4.112 MuCullough Building, 078.1, Univer- sity of Texas Medical Branch, Galveston, TX 77555-0783. 98