Granulomatous dermatitis with pseudoxanthoma elasticum-like changes: report of a case in a patient with cystic fibrosis.

BACKGROUND: There is scant literature that documents pseudoxanthoma elasticum (PXE)-like histologic changes in the setting of inflammatory skin diseases. This article documents granulomatous dermatitis with PXE-like changes in a patient with cystic fibrosis. This is the first report of its kind, to our knowledge. OBSERVATIONS: A 33-year-old woman with cystic fibrosis developed a papular eruption on the flexural surfaces of the upper and lower extremities, which was initially treated with prednisone. A punch biopsy showed granulomatous inflammation and associated PXE-like changes. The combined histologic and clinical findings were most consistent with granuloma annulare. There was no family history of PXE or clinical manifestations of PXE. The rash gradually resolved itself over the next several months. CONCLUSIONS: There are few publications that document PXE-like changes in association with various inflammatory skin conditions. Thus, the clinical significance of this finding remains uncertain. This case and previous reports are discussed in the context of current molecular and genetic knowledge. It is hoped that greater awareness of this phenomenon will promote further investigation and elucidation of the clinical and biologic significance of PXE-like changes observed in biopsies of inflammatory skin disorders.

Histiocyte-rich pleomorphic mastocytoma: an uncommon variant mimicking juvenile xanthogranuloma and Langerhans cell histiocytosis.

An 11-year old Caucasian female with a remote history of urticaria pigmentosa presented with a neck mass. A biopsy demonstrated a large intradermal nodule composed of unusually large epithelioid mast cells, including a prominent subset with bi-lobed and multi-lobed nuclei. By immunohistochemistry, the cells expressed CD117 (C-Kit), mast cell tryptase, CD68, and CD25, and were negative for CD163, CD1a, and S-100, confirming the diagnosis of mastocytoma. Equally prominent was an admixed infiltrate of CD68 and CD163-positive xanthomatous histiocytes that included Touton-type giant cells. Eosinophils were abundant. At 7 months follow-up, there was no recurrence of the lesion following complete excision. However, given the unusual cytologic features, close clinical observation is warranted, as the long-term biologic potential of mastocytoma with this degree of cytologic atypia is uncertain. Awareness of this unusual morphologic variant is also important as the histologic features may mimic such childhood neoplasms as juvenile xanthogranuloma and Langerhans cell histiocytosis.

An infiltrative variant of non-neural granular cell tumor: a case report.

Dermal non-neural granular cell tumors are rare tumors of indeterminate lineage that typically present as well-circumscribed tumors with nuclear pleomorphism and mitotic activity. We describe a dermal non-neural granular cell tumor with a distinctive growth pattern with granular cells interspersed between collagen bundles. This asymptomatic papule arose on the scapula of a 46-year-old woman and consisted of a mixture of epithelioid and spindled granular cells. The immunohistochemical characteristics were similar to those of previously reported dermal non-neural granular cell tumors. Despite mild nuclear pleomorphism and dispersion of lesional cells among collagen bundles, mitoses were not present and Ki-67 staining indicated a low proliferative rate. In addition to being S-100 protein negative and NKI/C3 positive, our case was positive for PGP9.5 and weakly positive for neuron-specific enolase, a staining pattern similar to what has been observed for cellular neurothekeomas. Our case could represent a dermal non-neural granular cell tumor with unique architecture, a granular cellular neurothekeoma or a granular cell dermatofibroma. As both dermal non-neural granular cell tumor and cellular neurothekeoma are of indeterminate lineage, our case with features characteristic of both entities may suggest a common precursor or lineage for dermal non-neural granular cell tumor and cellular neurothekeoma.

An 'eruptive' variant of juvenile xanthogranuloma associated with langerhans cell histiocytosis.

The development of juvenile xanthogranuloma (JXG) as a sequel to langerhans cell histiocytosis (LCH) treated with chemotherapy is rare and the hypothesis is intriguing. This is a case of a 19-year-old woman who presented with progressive development of tan-red papules on the axilla and eyelids over a 1.5-year time span. A biopsy of an axillary lesion showed a prominent dermal infiltrate of foamy histiocytoid cells with occasional Touton-type multinucleate giant cells, consistent with JXG. Three years later, the patient presented with additional similar papules on the axilla and vulva as well as a painful mass in the pelvic bone and diabetes insipidus with an associated pituitary mass. An iliac crest bone biopsy showed an eosinophil-rich infiltrate admixed with histiocytoid cells with reniform nuclei, which expressed S100 and CD1a, consistent with a diagnosis of LCH. Nonetheless, an additional axillary papule was once again consistent with JXG, with negative reaction for S100 and CD1a with no Birbeck granules by electron microscopy. This case is unique by the co-existing presentation of multiple cutaneous JXG lesions and internally confined LCH lesions without an apparently associated chemotherapy, corroborating the concept that JXG and LCH may share a common histogenesis.