Johnson, Emma F.

AbstractBackgroundIntravascular histiocytosis is an underrecognized reactive skin condition characterized by the clinical finding of poorly demarcated erythematous to violaceous patches and plaques. The diagnosis is confirmed by the histologic findings of intraluminal histiocytes on skin biopsy and exclusion of an alternative diagnosis.MethodsA review of patients with a histologic diagnosis of intravascular or intralymphatic histiocytosis and seen at Mayo Clinic, Rochester, Minnesota, from January 1, 2010, to October 10, 2020, was performed. Histologic and clinical information was collected from the medical records.ResultsNine patients were identified. Clinical impressions prior to biopsy varied widely, and no clinician included intravascular histiocytosis in the initial clinical differential diagnosis. Eight patients had preceding trauma to the affected area.ConclusionIntravascular histiocytosis remains a rare skin condition. Clinical identification remains low. Our cases add support to the hypothesis that intravascular histiocytosis is a reactive condition often preceded by trauma and/or surgery.

AbstractBackgroundMycosis fungoides (MF) is characterized by epidermotropic atypical lymphocytes in the absence of spongiosis. However, we describe an unusual presentation of MF with spongiosis, mimicking benign inflammatory dermatoses and highlight the importance of pathologic interpretation for diagnostic confirmation.MethodsA cross‐sectional study of consecutive patients diagnosed with MF with spongiosis was conducted. The clinical, histopathologic, immunophenotypic, and molecular genetic features of cases were reviewed.ResultsWe identified nine cases of MF (age range 34‐82 years; mean 75 years), with an initial diagnosis of dermatitis (6/9), psoriasis (4/9), or other inflammatory dermatoses (2/9). Pruritus, pain, and blisters were common clinical manifestations. The most common areas of involvement were the extremities (8/9). Epidermotropism with spongiosis was a central histopathological feature in all cases.ConclusionThese cases highlight prominent spongiosis in MF and overlap with common benign inflammatory dermatoses. We present these cases to show the diagnostic pitfalls associated with spongiotic presentations of MF. Dermatitis, psoriasis, and other inflammatory skin conditions not responsive to standard therapy warrant further work‐up including biopsy to rule out MF. Multiple skin biopsies and review by a dermatopathologist with expertise in the diagnosis of cutaneous lymphoma is highly recommended.

SummaryBackgroundAlpha‐1 antitrypsin deficiency (AATD) may be associated with liver and lung disease and rarely causes panniculitis.ObjectiveWe evaluated the clinicopathologic and laboratory findings of AATD panniculitis in 10 patients.MethodsWe conducted a retrospective review of all cases of AATD panniculitis at Mayo Clinic, Rochester, MN, from 1989 to 2016.ResultsTen patients with AATD panniculitis were included. Seven of ten were women. Clinical lesions were most commonly nodular (100%), erythematous (90%), ulcerated (90%), and painful (90%) subcutaneous nodules and plaques. Extracutaneous associations were rare. PiZZ phenotype was most commonly identified (50%). Histopathologically, lobular panniculitis (80%) with associated septal involvement (60%) and a predominant neutrophilic infiltrate (100%) were most common. Treatments varied; dapsone and alpha‐1 proteinase inhibitor infusions were each used in five (50%) patients, respectively. In patients with greater than 6‐month follow‐up (n = 4), one patient continued to have disease activity despite treatment.ConclusionAATD panniculitis should be considered in the differential for a painful, ulcerative panniculitis with a predominantly neutrophilic histopathologic infiltrate. Diagnosis can be made with clinicopathologic correlation and genetic and laboratory evaluations. Serum AAT level and phenotype assists in diagnosing patients with suspected AATD panniculitis.

Abstract: Vascular tumors in infants present a diagnostic and treatment dilemma for both clinicians and pathologists. Infantile hemangioma, the most common vascular tumor in infants, can be confused for other less common vascular tumors in infants. Correct and timely diagnosis is important, as some vascular tumors can be associated with life-threatening coagulopathy. We present the cases of 5 vascular tumors that have clinical and histologic overlap: infantile hemangioma, pyogenic granuloma, noninvoluting congenital hemangioma, tufted angioma, and kaposiform hemangioendothelioma. Typical clinical and histopathologic features of each lesion are summarized. We review the utility and characteristic immunohistochemistry including CD31, CD34, GLUT-1, D2-40, LYVE-1, Prox-1, and WT-1. Collaboration between the clinician and the dermatopathologist correlating the clinical history and histopathologic features can lead to the correct diagnosis, whereas the utility of immunohistochemistry remains in question.

AbstractBackgroundLeukocytoclastic vasculitis (LCV) in children is a complex group of conditions.ObjectivesThis study presents the demographics, clinical features, direct immunofluorescence (DIF) results and suspected aetiologies of 56 biopsy‐confirmed cases of leukocytoclastic vasculitis in children.MethodsRetrospective review of 56 children seen at Mayo Clinic in Rochester, Minnesota, from 1993 to 2013 with clinical features and cutaneous biopsy consistent with LCV.ResultsTwenty‐seven (48%) cases were found to be due to IgA vasculitis (Henoch‐Schonlein purpura). The remaining cases were found to be due to cutaneous small‐vessel vasculitis (n = 19, 34%), urticarial vasculitis (n = 5, 9%), ANCA‐associated vasculitis (n = 4, 7%) and acute haemorrhagic oedema of infancy (n = 1, 2%). IgA vasculitis was found to be associated with abdominal pain (P = 0.008), whereas the non‐IgA vasculitis group was associated with headache (P = 0.052). Children with IgA vasculitis had palpable purpura (P = <0.001), petechia (P = 0.057), vesicles (P = 0.009) and involvement of the buttock (P = 0.004) more frequently than the non‐IgA vasculitis group. On DIF, perivascular IgA was positive in IgA vasculitis compared to non‐IgA vasculitis cases (P = <0.001), the other conjugates were similar between the two groups.ConclusionThe most common subtype of biopsy‐confirmed LCV in children is IgA vasculitis. Clinical features, exam characteristics and DIF results can be helpful in determining the subtype of cutaneous vasculitis in children.