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Objectives This study was aimed to investigate the significance of unexpected vasculitis identified in gastrointestinal (GI) specimens by determining its prevalence and correlation with clinical outcomes. Methods GI specimens with histologic evidence of vasculitis were identified in our pathology database over a 10-year period (January 2008 to August 2018). Clinical history, treatment, and follow-up were reviewed. Results Of the 131,367 GI pathology cases received over the 10-year study period, 29 (0.02%) cases showed histologic evidence of GI vasculitis. The majority (69%, 20/29) were not clinically suspected. Of these, 20% (4/20) of patients were subsequently diagnosed with systemic vasculitis. During the mean follow-up period of 34.0 months, 24% (4/17) of the patients with this unexpected diagnosis died as the result of direct complications of GI vasculitis. We also found that 95% of cases with unexpected vasculitis in their GI pathology specimens were communicated in a timely manner to the ordering physicians, which necessitated the immediate initiation of additional workups in 85% of these patients. Conclusions The GI involvement of vasculitis is rarely encountered by pathologists, but its diagnosis carries tremendous clinical significance with a high mortality rate. Therefore, timely communication is highly recommended for the early diagnosis and treatment of this disease.

Langerhans cell histiocytosis (LCH) is a clonal neoplastic proliferation of Langerhans-type cells. Orbital LCH is infrequent, typically manifesting as an isolated lytic bony lesion with an adjacent soft tissue mass in a child. Isolated lacrimal gland involvement by LCH is extremely rare, with only 2 previously reported cases. The authors describe a 37-year-old woman with a 6-month history of painless right upper eyelid swelling and diffuse right lacrimal gland enlargement without bony changes on computed tomography scan. Excisional biopsy of the lacrimal gland demonstrated concurrent LCH, extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue, and increased IgG4-expressing plasma cells. Work-up was negative for systemic hematolymphoid malignancy and IgG4-related disease. This case illustrates the association between LCH, mucosa-associated lymphoid tissue lymphoma, and elevated IgG4 plasma cells in the lacrimal gland, and we review the emerging theories proposed to explain this phenomenon.

Introduction. Macrophages are phenotypically heterogeneous cells that play a vital role in hepatic fibrogenesis. We aimed to compare the macrophage profiles between normal livers and those with various chronic liver diseases in the precirrhotic fibrosis stage. Methods. Immunohistochemistry was performed for three macrophage markers (CD163, CD68, and IBA1) on 48 liver biopsies. Digital image analysis and automated cell count were used to calculate the densities of immunostained cells in two selected regions of interest: the periportal region and the perivenous region. Results. The absolute and relative densities of the macrophage phenotypes in relationship with zones and etiologies showed four distinct patterns by hierarchical cluster analysis: (1) no significant increase in the macrophage densities in either periportal or perivenous regions - nonalcoholic steatohepatitis; (2) significant increase in the selected macrophage densities in both periportal and perivenous regions - Hepatitis C; (3) significant increase in the macrophage densities only in periportal region - alcoholic liver disease, primary sclerosing cholangitis, and primary biliary cholangitis; and (4) significant increase in the densities of all types of macrophages in both periportal and perivenous regions - autoimmune hepatitis. Conclusions. There are distinct macrophage phenotypic and zonal geographic signatures correlating to etiologies of chronic liver disease in the precirrhotic stage.