No abstract

Infection with Histoplasma capsulatum typically manifests as a self-limiting pulmonary disease in immunocompetent patients. Systemic symptoms such as cutaneous lesions are associated with immunodeficient states. Our patient was an immunocompetent 68-year-old male who presented with a plaque on his left infraorbital area that was concerning for malignancy. Histological examination of the lesion revealed granulomatous inflammation and small yeast forms suggestive of H. capsulatum. The lesion resolved spontaneously and recurred 1 year later. On recurrence, histological examination again revealed yeast forms consistent with H. capsulatum. Serum and urine testing for H. capsulatum antigen were negative. Next-generation sequencing detected H. capsulatum, which supported the diagnosis of a cutaneous infection. The patient was prescribed and started treatment with itraconazole for 1 year after recurrence of the lesion, and he has not reported further disease recurrence to date. This case is unique because of the presentation of a primary cutaneous recurrent H. capsulatum lesion, and it demonstrated the utility of laboratory testing in its diagnosis.

Semaglutide has little hepatic metabolism and is deemed low risk for causing drug-induced liver injury (DILI). We present a case of DILI from the US DILI Network. The case involved a 51-year-old man with type 2 diabetes who presented with jaundice and acuteon-chronic kidney disease 6 months after starting oral semaglutide. His liver injury progressed to biliary cirrhosis, accompanied by nephritis that led to end-stage renal disease. Extensive evaluations including liver and kidney biopsies revealed no alternative etiologies. Cholestatic gene sequencing revealed heterozygosity for ABCC2 and DHCR7. He eventually underwent combined liver and kidney transplantation.

Casestudy: Pathologic diagnosis of chronic myelomonocytic leukemia (CMML) is typically straightforward with the majority of patients presenting with persistent monocytosis (>1x109/L, >=10%) and bone marrow dysplasia. The diagnosis may be challenging in patients with unusual features such as lack pf peripheral blood monocytosis and non-diagnostic bone marrow morphology. In this abstract, we present a 67-year-old female with a 5-year history of anemia of unclear etiology. At the time of initial presentation, the laboratory work-up of normocytic anemia was non- contributory, the bone marrow was reported as normocellular with maturing trilineage hematopoiesis and no significant dysplasia. Over the course of the disease, the peripheral blood monocyte count fluctuated from 11% to 18% with absolute monocyte count ranging from 0.4 to 0.7x109/L. The most recent bone marrow was markedly hypercellular with increased trilineage hematopoiesis with left shift, dysgranulopoiesis and dysmegakaryopoiesis. Blasts (including promonocytes) constituted 10% of the differential count and were immunophenotypically abnormal with uniform expression of CD117, dim to negative CD13, and partial CD15. Monocytes were elevated at 12% and were strongly positive for CD64 and partially for CD14. They were negative for CD16 consistent with classical monocytes, and showed partial loss of CD13. The karyotype was normal. Molecular testing revealed TET2, RELN and SRSF2 mutations at high allelic frequencies. This case illustrates a value of flow cytometric immunophenotyping and molecular genetic studies in diagnosing challenging cases of CMML. While the patient’s absolute monocyte count remained below the diagnostic threshold of 1x109/L throughout the course of the disease, peripheral blood and bone marrow monocytes showed skewed classical immunophenotype, immunophenotypic abnormalities of myeloid series and high allelic frequency mutations. These findings should raise a differential diagnosis of oligomonocytic CMML, even when morphologic abnormalities and monocyte count threshold are not diagnostic.

Previous facial motoneuron (MN) survival studies have identified a facial MN population that is resilient to axotomy. Examination of the literature suggests two distinct populations of MN: one population vulnerable to axotomy and another population potentially resilient to axotomy. To identify potential differences in MN survival levels after target disconnection, we performed a facial nerve transection at the stylomastoid foramen in a number of different mouse strains, as well as models of immunodeficiency and MN disease. All mice were monitored for facial MN survival for up to 26 weeks post‐axotomy (wpa). We observed an 85% survival of facial MN at 4 wpa that was reduced to about 50% at 10 wpa in WT mice. In contrast, facial MN survival significantly dropped at 4 wpa to approximately 62% and 50% in immunodeficient and MN disease mice, respectively. Similar to WT mice, facial MN survival levels remained at about 50% for up to 18 wpa in both the immunodeficient and MN disease mice. Collectively, these data suggest that, despite target disconnection of similar MN populations by either axotomy or disease, there are inherent differences that may be exploited for therapeutic applications in the future.