A photo of Oscar Lopez-Nunez.

Staff Pathologist, Division of Pathology and Laboratory Medicine

Associate Program Director, Pediatric Pathology Fellowship Program

Assistant Professor, UC Department of Pathology and Laboratory Medicine


Board Certified

"I am aware of the enormous impact my diagnoses could have on children’s lives and the lives of their families. I approach each one of my patients with the same level of empathy and care as I would with my own children."

My Biography & Research


As a pediatric pathologist, I am aware of the enormous impact my diagnoses could have on children’s lives and the lives of their families. I approach each one of my patients with the same level of empathy and care as I would with my own children.

I was inspired to pursue pathology over many years of training, where I developed a particular interest in studying disease mechanisms. As a pathology trainee, my personal experiences as a father and my fascination with understanding pediatric oncologic diseases helped me realize how deeply I care for children. So, I became a pediatric pathologist.

I consider myself to be an essential part of an interdisciplinary team. By spending quality time at the microscope, providing a comprehensive pathologic assessment in my reports and maintaining continuous communication with my clinical colleagues, I strive to achieve the correct diagnoses and the best care in every case.

Although my little patients and their families probably will not see me, I do see them. To me, every glass slide under my microscope is a small window into a child’s life. I want families to know I’m committed to providing the best care possible every time I render a diagnosis — no matter how simple or complex.

My areas of research include molecular characterization of bone and soft tissue tumors, like sarcomas. Many of these tumors show aggressive biologic behavior and the identification of molecular signatures can be beneficial from a diagnostic and a therapeutic point of view. I am also interested in the pathobiological mechanisms of pediatric eosinophilic disorders and inflammatory gastrointestinal diseases.

I love spending my free time with my wife and son doing outdoor activities, like hiking and biking. I also enjoy gardening outdoors. Among other things, I love freestyle drawing and illustration — a skill that I often use when spending time with my son or while creating online educational content for my peers in pathology.

Academic Affiliation

Assistant Professor, UC Department of Pathology and Laboratory Medicine

Clinical Divisions

Pathology, Inflammatory Bowel Disease

Research Divisions


My Education

MD: Universidad Dr. Jose Matias Delgado, Escuela de Medicina, Antiguo Cuscatlan, El Salvador.

Residency: Anatomic and Clinical Pathology, Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, PA.

Fellowship: Department of Pathology, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA.

Certification: Educational Commission of Foreign Medical Graduates (ECFMG).

My Publications

Pediatric decision limits for serologic screening of Lyme disease. Lopez-Nunez, O; Srivastava, P; Wheeler, BJ; Oakes, N; Thomas, H; Nowalk, A; Wheeler, S. Clinical Biochemistry. 2021; 91:59-62.

Melanotic Neuroectodermal Tumor of Infancy (MNTI) and Pineal Anlage Tumor (PAT) Harbor A Medulloblastoma Signature by DNA Methylation Profiling. Lopez-Nunez, O; Alaggio, R; John, I; Ciolfi, A; Pedace, L; Mastronuzzi, A; Gianno, F; Giangaspero, F; Rossi, S; Donofrio, V; et al. Cancers. 2021; 13.

Novel APOD-GLI1 rearrangement in a sarcoma of unknown lineage. Lopez-Nunez, O; Surrey, LF; Alaggio, R; Herradura, A; McGough, RL; John, I. Histopathology. 2021; 78:338-340.

The spectrum of rare central nervous system (CNS) tumors with EWSR1-non-ETS fusions: experience from three pediatric institutions with review of the literature. Lopez-Nunez, O; Cafferata, B; Santi, M; Ranganathan, S; Pearce, TM; Kulich, SM; Bailey, KM; Broniscer, A; Rossi, S; Zin, A; et al. Brain Pathology. 2021; 31:70-83.

Immunohistochemical Expression Analysis of EpCAM in Hepatoblastomas. Lopez-Nunez, O; Ranganathan, S. Applied Immunohistochemistry and Molecular Morphology. 2020; 28:711-718.

New molecular insights into the pathogenesis of lipoblastomas: clinicopathologic, immunohistochemical, and molecular analysis in pediatric cases. Lopez-Nunez, O; Alaggio, R; Ranganathan, S; Schmitt, L; John, I; Church, AJ; Picarsic, J. Human Pathology. 2020; 104:30-41.

Novel PPP1CB-ALK fusion in spindle cell tumor defined by S100 and CD34 coexpression and distinctive stromal and perivascular hyalinization. Lopez-Nunez, O; Surrey, LF; Alaggio, R; Fritchie, KJ; John, I. Genes Chromosomes and Cancer. 2020; 59:495-499.

Infantile inflammatory myofibroblastic tumors: clinicopathological and molecular characterization of 12 cases. Lopez-Nunez, O; John, I; Panasiti, RN; Ranganathan, S; Santoro, L; Grelaud, D; Wu, T; Buccoliero, AM; Casanova, M; Alaggio, R; et al. Modern Pathology. 2020; 33:576-590.

Case of Sudden Acute Coma Followed by Spontaneous Recovery. Lopez Nunez, OF; Rymer, JA; Tamama, K. Journal of Applied Laboratory Medicine. 2018; 3:507-510.

Ricin Poisoning after Oral Ingestion of Castor Beans: A Case Report and Review of the Literature and Laboratory Testing. Lopez Nunez, OF; Pizon, AF; Tamama, K. Journal of Emergency Medicine. 2017; 53:e67-e71.