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Ochronosis is the blue-gray discoloration of collagen-containing tissues due to homogentisic acid (HGA) deposition, secondary to endogenous alkaptonuria or exogenous enzyme inhibition. In renal disease, accumulation of HGA in serum can cause methemoglobinemia. A 60-year-old woman with renal disease and anemia presented with 3 days of weakness and months of gray skin discoloration. Her hemoglobin was 8.1g/dl with 24.5% methemoglobin. Despite treatment with methylene blue, exchange transfusion, and continuous renal replacement therapy, the patient died. Autopsy revealed gray discoloration and ochronotic pigment in the ribs and cartilage. Based on these findings, the patient was diagnosed with ochronosis, suggestive of alkaptonuria, complicated by methemoglobinemia. The differential diagnosis for blue-gray skin discoloration includes argyria, methemoglobinemia, and ochronosis. This patient's clinical and autopsy findings suggested alkaptonuria complicated by methemoglobinemia due to progressive renal dysfunction. Development of methemoglobinemia in the setting of chronic skin discoloration and renal failure should prompt consideration of alkaptonuria.

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e12531 Background: Mixed Invasive Ductal-Lobular Carcinoma (IDC-L) is a histological subtype of invasive breast carcinoma comprised of both ductal and lobular morphologies. There is limited information on the relative proportions of the individual components in IDC-L and on outcomes compared to invasive lobular carcinoma (ILC) and invasive ductal carcinoma (IDC). Methods: Clinical information was abstracted from 16,308 patients with invasive breast cancer seen at UPMC Magee Women’s Hospital from 1990-2017 using the UPMC Network Cancer Registry. A systematic chart review was performed on a subset of patients annotated with IDC-L (n=806); however, a thorough review of pathology reports led to the exclusion of all but 408 patients for further analysis, due to the lack of a standardized definition of IDC-L. Of the 408 cases, 92% were estrogen receptor (ER)+. Survival of patients with ER+ IDC-L (n=376) was compared to ER+ IDC (n=9,716) and ER+ ILC (1,465). For a subset of IDC-L cases (n=54), distributions of individual subtype components were abstracted from pathology reports. Results: IDC-L made up 2.5% of the total cases (408/16,308). IDC-L tumors were on average 31% ductal and 69% lobular (p =0.001). Survival analysis showed worse disease free survival (DFS) (p=0.05) and overall survival (OS) (p=0.002) in patients with ER+ ILC compared to ER+ IDC, with ER+ IDC-L patients showing a median OS superior to ILC yet inferior to IDC counterparts (ns). Conclusions: Identification of patients with IDC-L through cancer registry protocols representative of standard practices by national cancer registries revealed a lack of a standardized definition of mixed IDC-L. Reliance on accuracy of these diagnoses calls in to question the reliability of prior clinico-pathologic analyses reported on this topic. DFS and OS of IDC-L patients falls between that of IDC and ILC patients while ILC patients showed significantly worse outcome. The predominant distribution of lobular morphology in IDC-L tumors suggests this subtype may have additional characteristics similar to lobular rather than ductal carcinomas. Comprehensive clinical and molecular characterization of a carefully identified IDC-L cohort is underway.