Persistent polymorphous light eruption after ultraviolet A1 phototherapy.

Polymorphous light eruption (PMLE) is the most common photodermatosis and is characterized by the development of a pruritic skin eruption within a few hours to days after sun or artificial light exposure. The eruption usually takes up to two weeks to resolve in the absence of further ultraviolet radiation. PMLE has been reported as a side effect of ultraviolet A1 (UVA1) therapy but characteristics of the eruption, especially the duration until resolution after treatment, has not been described. A 37-year-old female developed an unusually persistent PMLE that lasted for 5 weeks after completion of UVA1 phototherapy.

Lobular panniculitis at the site of subcutaneous interferon beta injections for the treatment of multiple sclerosis can histologically mimic pancreatic panniculitis. A study of 12 cases.

BACKGROUND: Thrombosis, mucinosis and necrosis are well-described complications of subcutaneous interferon beta injections. METHODS: We report 12 incisional biopsies from subcutaneous interferon beta injection sites in 12 multiple sclerosis (MS) patients from a single neurologist's practice. RESULTS: We identified abscesses (two cases) or induration (two cases) in acute clinical lesions and lipoatrophy (eight cases) in chronic lesions (biopsied over a year after symptom onset at injection sites). Biopsies from three acute lesions showed vascular thrombosis, dermal mucinosis, lobular neutrophilic panniculitis, necrosis, calcification and hemosiderin deposition (biopsied 2 weeks to 2 months after symptom onset). Two cases contained sterile abscesses. Five of the eight chronic cases presented as hard, indurated lipoatrophy with livedo reticularis. Their biopsies showed subcutaneous calcification and lipoatrophy. Biopsies from the early calcific suppurative and late calcific atrophic phases histologically resembled the early and late phases of subcutaneous saponification in pancreatic panniculitis. CONCLUSIONS: Reactions at the site of subcutaneous interferon beta injections are common. Lipoatrophy can be clinically identified in 39 of 85 MS patients (46%) receiving subcutaneous interferon beta injections for 1 year or longer in our practice. A reaction to interferon should be considered in the differential diagnosis of biopsies that show features of pancreatic panniculitis.

Lobular panniculitis at the site of glatiramer acetate injections for the treatment of relapsing-remitting multiple sclerosis. A report of two cases.

Lipoatrophy and localized panniculitis have been described as rare complications of daily subcutaneous glatiramer acetate injections for the treatment of relapsing-remitting multiple sclerosis (MS). We describe the biopsies from two MS patients in a single neurologist's practice who developed clinical lesions of lipoatrophy at the sites of subcutaneous glatiramer acetate injections. These biopsies showed a lobular panniculitis with lipoatrophy that more closely resembled lupus panniculitis than previous reports of localized panniculitis at glatiramer acetate injection sites. In one case, the area of clinical lipoatrophy continued to enlarge for 6 months after stopping glatiramer acetate therapy, before stabilizing at its current size for the last 8 months. Injection site reactions to glatiramer acetate should be considered in the differential diagnosis of biopsies that show a lupus panniculitis-like appearance. Our observations indicate that glatiramer acetate induced panniculitis is common and may continue to progress after therapy has stopped. In this single neurologist's practice, 64% of the patients receiving daily glatiramer acetate injections had clinical evidence of lipoatrophy or panniculitis. Of 100 consecutive patients receiving therapy for MS between February and November 2006, 14 patients were on glatiramer acetate, 9 of whom had clinical lipoatrophy.

Merkel cell carcinoma frequently shows histologic features of basal cell carcinoma: a study of 30 cases.

BACKGROUND: Merkel cell carcinoma (MCC) is a basaloid cutaneous neoplasm that may be mistaken for basal cell carcinoma (BCC). METHODS: Thirty MCCs were examined for areas that histologically resembled BCC. RESULTS: One of the histologic features of BCC (either a mucinous stroma or stromal artifactual retraction) was identified in all MCCs. A mucinous stroma was found in 28 MCCs (93%), stromal artifactual retraction in 27 (90%), mucin-containing gland-like spaces within tumor nests in 8 (27%), focal peripheral palisading in 8 (27%), epidermal involvement in 3 (10%) and dystrophic calcification in 1 MCC (3%). The cytologic features and absence of widespread peripheral palisading were the most reliable discriminators between MCC and BCC on routine sections. Squamous cell carcinoma was identified in four cases (13%). Two cases (7%) contained pagetoid intraepidermal spread (IES) of MCC. In one case, there was IES over the entire epidermal surface associated with intranuclear clearing, resembling the intranuclear cytoplasmic inclusions (INI) common in melanocytic tumors. INI were identified in six MCCs (20%). CONCLUSIONS: MCCs frequently contain areas that histologically resemble BCC and other more common cutaneous malignancies. This can lead to diagnostic errors, particularly in small fragmented curettage specimens or frozen sections.

Melanocytic nevi are associated with neurofibromas in neurofibromatosis, type I, but not sporadic neurofibromas: a study of 226 cases.

BACKGROUND: Neurofibromatosis, type 1, is associated with cutaneous melanin pigmentation, but an association with ordinary melanocytic nevi has not been described. METHODS: This retrospective case-control study was designed to see if neurofibromas in patients with neurofibromatosis, type 1 (NF-1) differ from sporadic neurofibromas (SN) in their incidence of associated melanocytic nevi and other histologic features. Slides from 114 NF-1 were compared with 112 SN and 300 intradermal melanocytic nevi (IDN). RESULTS: Small lentiginous melanocytic nevi were identified over 13 NF-1 (11%) but no SN (P=0.0002). Compared with other NF-1, NF-1 with nevi were more frequently associated with melanocytic hyperplasia, giant melanosomes and diffuse neurofibroma (P<0.03). Compared with SN, NF-1 were also more frequently associated with melanocytic hyperplasia, lentigo simplex-like changes, diffuse neurofibroma and plexiform neurofibroma (P<0.001). Sebaceous hyperplasia (14%), dermal elastosis (9%), lipomatous change (8%), epithelial cysts (4%) and keratin granulomas or folliculitis (3%) were not significantly different in prevalence between NF-1, SN and the control group of IDN. CONCLUSIONS: This study suggests that there is a difference in the potential for melanocytic proliferation in NF-1 compared with SN. NF-1, SN and IDN are associated with a similar range of incidental histologic changes. Ball NJ, Kho GT. Melanocytic nevi are associated with neurofibromas in neurofibromatosis, type 1, but not sporadic neurofibromas. A study of 226 cases.

The histologic spectrum of cutaneous sarcoidosis: a study of twenty-eight cases.

BACKGROUND: Naked sarcoidal granulomas (NSGs) are the characteristic histologic finding in sarcoidosis. This descriptive study was designed to identify the frequency of other histologic changes in cutaneous sarcoidosis. METHODS: The slides from 28 sequential biopsies previously diagnosed as sarcoidosis in patients with known systemic sarcoidosis were reviewed. RESULTS: Classic NSGs were identified in 25 biopsies (89%). Four biopsies contained tuberculoid granulomas, two with neutrophils suggesting infection (cultures negative). Five biopsies contained interstitial granulomas that resembled granuloma annulare and necrobiosis lipoidica in one case each. Additional histologic findings included birefringent foreign material in 14 biopsies (50%), focal necrosis (43%), elastophagocytosis (39%), linear peri-neural granulomas resembling leprosy (25%), increased dermal mucin (18%) and lichenoid inflammation (14%) [two with plasma cells resembling syphilis (7%)]. In all but three cases, the clinical morphology of the lesions suggested sarcoidosis. Special stains for mycobacteria and fungi were negative. CONCLUSIONS: The histologic changes in cutaneous sarcoidosis are more diverse than previously recognized. In sarcoidosis, foreign material may be a frequent nidus for cutaneous granuloma formation. Histologic examination without the clinical history could lead to a misdiagnosis of leprosy, syphilis, other infectious granulomas, rosacea, granuloma annulare, necrobiosis lipoidica, and foreign body reaction in selected cases from this series.

Kikuchi-Fujimoto's necrotizing lymphadenitis in association with discoid lupus erthematosus: a case report.

BACKGROUND: Kikuchi-Fujimoto's necrotizing lymphadenitis (KFNL) is a rare, benign, self-limited condition characterized by constitutional symptoms, lymphadenopathy, and skin lesions. OBJECTIVE: We report a case of KFNL in a 43-year-old East Indian woman with a ten-year history of discoid lupus erythematosus (DLE) of the scalp and a three-month history of a erythematous plaque on the left nasal bridge, cervical lymphadenopathy, and fever. Skin biopsy samples were taken from the face and lymph node. RESULTS: Histopathological examination of the skin revealed a mixed infiltrate of inflammatory cells, nuclear dust, and histiocytes phagocytosing nuclear debris in the reticular dermis. The lymph node showed interfollicular liquefactive necrosis, immunoblasts, and a similar cellular infiltrate as the skin. The non-necrotic areas demonstrated follicular hyperplasia. These pathological changes are associated with a diagnosis of KFNL. CONCLUSIONS: KFNL is reported in association with systemic lupus erythematosus, but only two other cases of systemic KFNL in association with DLE exist in the literature. This case is unique in that the patient presented with cutaneous and systemic KFNL in the setting of longstanding DLE.

Psoriasiform dermatitis susceptibility in Itgb2(tm1Bay) PL/J mice requires low-level CD18 expression and at least two additional loci for progression to severe disease.

Itgb2(tm1Bay) PL/J mice express low levels of the beta(2) integrins and, unlike Itgb2(tm1Bay) C57BL/6J mice, spontaneously develop psoriasiform dermatitis with several similarities to human psoriasis. To define the genetic requirements for skin disease susceptibility we analyzed more than 500 F2 progeny from an Itgb2(tm1Bay) (PL/J x C57BL/6J) intercross. We found that 23.5% developed chronic inflammatory skin disease, although significant differences in severity were observed. Another CD18 mutation, Itgb2(tm2Bay), has now been generated that completely eliminates CD18 expression. Surprisingly, of 10 Itgb2(tm2Bay) homozygote PL/J N4 mice generated, none showed clinical or histopathological evidence of disease. However, Itgb2(tm1Bay)/Itgb2(tm2Bay) PL/J mice developed dermatitis indistinguishable from Itgb2(tm1Bay) PL/J mice. In addition, approximately half of Itgb2(tm1Bay)/Itgb2(tm2Bay) (C57BL/6J x PL/J)F1 mice were found to develop mild psoriasiform dermatitis identical to the early stages of disease seen in Itgb2(tm1Bay) PL/J mice. Collectively, these results suggest a complex inheritance pattern of psoriasiform dermatitis in this model that involves lowered, but not absent, CD18 expression and at least two additional PL/J loci for the development of severe disease. The susceptibility allele can act in either a heterozygous or homozygous state, dependent on the level of CD18 expression.