Common Symptom, Rare Etiology: A Case Metastatic Cancers of Unknown Primary Origin Presenting with Epistaxis and Gingival Bleeding

Introduction: Epistaxis and gingival bleeding are among the most common presentation to the emergency department for patients with thrombocytopenia. Here, we present a case who was admitted to the emergency department with thrombocytopenia and was diagnosed with metastatic cancer of unknown primary origin. Case Report: A 26-year-old male patient was admitted to the emergency department with gingival bleeding and epistaxis. The body temperature was 38.3 °C. Petechial rash, ecchymosis or organomegaly was not detected on physical examination. Laboratory results revealed thrombocytopenia as 31 × 103 (159-388 × 103/μL). Although hemoglobin and leukocyte counts were normal, no band or precursor cell was observed in the patient's peripheral blood smear. There was no history of weight loss, night sweats, arthritis, malar rash, photosensitivity, contact with ticks, animals, or a COVID-19 patient. Serological tests performed for infections such as HIV, EBV, HCV, Crimean-Congo hemorrhagic fever were negative. Bone marrow biopsy was performed due to the unexplained cytopenia, reported as "signet ring cell metastatic adenocarcinoma". Gastrointestinal system endoscopy was performed to detect primary cancer. A biopsy was taken from the antrum and corpus revealed gastritis. An FDG PET-CT was revealed heterogeneously pathologically increased FDG attitude in all axial and appendicular bones. Despite all the modalities of diagnosis, the origin was not found and the patient was transferred to the oncology department for treatment with a diagnosis of cancer of unknown origin with bone marrow infiltration. Conclusion: Bone marrow metastases should be kept in mind in patients presenting with thrombocytopenia.