Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a rare autosomal recessive disorder. The mutation in the ECGF1 gene causes severe deficiency of thymidine phosphorylase (TP), which in turn increases thymidine and deoxyuridine in the blood, serum, and tissue. The toxic levels of these products cause malfunction of the mitochondrial respiratory chain and mitochondrial DNA. Commonly, patients become symptomatic between 15 and 20 years of age (range 5 months to 35 years). The most commonly affected systems are gastrointestinal, followed by ocular, and nervous system. The disease is often fatal; high mortality rate is reported between 20 and 40 years of age. Treatment modalities that can increase thymidine phosphorylase activity and decrease thymidine and deoxy-uridine have shown symptomatic improvements in patients with MNGIE. Platelet transfusion, hemodialysis, peritoneal dialysis or allogeneic hematopoietic stem cell transplantation (HSCT) have been tried. The survival and long-term benefits of these measures are still not clear. Engrafted patients after stem cell transplantation have showed improvements in serum thymidine and deoxyuridine. We are reporting a case of MNGIE from Saudi Arabia, who underwent allogeneic hematopoietic stem cell transplantation. No MNGIE case has been previously reported from Saudi Arabia or the Gulf Arab countries. From the available literature, so far only 11 patients with MNGIE have undergone stem cell transplantation.

Klebsiella oxytoca can cause various infectious complications in healthy as well as in immunocompromised individuals. Case 1: A 49 year old female with multiple myeloma received an autologous hematopoietic stem cell transplant in October 2005. Eight days following her autograft she developed septic shock caused by Klebsiella oxytoca bacteremia which was successfully treated with intravenous meropenem and gentamicin. Case 2: A 29 year old female with sickle cell anemia and severe aplastic anemia underwent an allogeneic hematopoietic stem cell transplant in July 2005. Seven months following her unsuccessful allograft, she developed septic shock due to Klebsiella oxytoca bacteremia caused by a urinary tract infection. The septic episode was successfully managed with intravenous meropenem and gentamicin. Both patients were treated at King Faisal Specialist Hospital and Research Centre in Riyadh, Saudi Arabia. To our knowledge, they are the first reports of Klebsiella oxytoca bacteremias and septic shocks in hematopoietic stem cell transplant recipients. Klebsiella oxytoca should be considered as a possible cause of severe infections in recipients of various forms of hematopoietic stem cell transplantation. However, these infections may be complicated by bacteremias, septic shocks, systemic dysfunctions and even deaths if not managed promptly and appropriately.

Plasma cell leukemia (PCL) is a rare hematologic malignancy with very poor outcome. It is defined by the presence of >2 × 10 ⁹ /L plasma cells or >20%s plasmacytosis of the differential white cell count in the peripheral blood. Primary PCL is first diagnosed in the leukemic phase, while secondary PCL corresponds to the leukemic transformation of a previously diagnosed multiple myeloma (MM). The incidence of PCL ranges between 2-4% of patients with MM and 0.9% of patients with acute leukemia. In this case series, we describe the clinicopathologic, immunophenotypic, and cytogenetic findings of four patients diagnosed with PCL within a ten-year period (2002-2012) at King Faisal Specialist Hospital and Research Centre (General Organization), Riyadh, Saudi Arabia.

Chemotherapy-induced cytopenia (CIC) is characterized by neutropenia, anemia, and thrombocytopenia, which are common and serious complications in cancer treatment. These conditions affect approximately 60% of patients undergoing chemotherapy and can significantly impact quality of life, treatment continuity, and overall survival. The use of growth factors, including granulocyte colony-stimulating factors (GCSFs), erythropoietin-stimulating agents (ESAs), and thrombopoietin receptor agonists (TPO-RAs), has emerged as a promising strategy for managing CIC. However, the use of these growth factors must be approached with caution. This review provides an overview of the mechanisms, efficacy, and safety of growth factors in the management of CIC. Additionally, we discuss predictive markers for treatment response, potential risks, and highlight areas for future research.

Sickle cell disease (SCD) is a hereditary hemoglobin disorder characterized by chronic hemolysis and recurrent vaso-occlusive crises, leading to a wide spectrum of complications. While common SCD manifestations have well-established management protocols, rare and atypical complications pose significant diagnostic and therapeutic challenges. A critical barrier is diagnostic overshadowing, where common SCD symptoms (pain, fever, respiratory distress) mask infrequent but life-threatening conditions, resulting in delayed recognition and suboptimal outcomes. This narrative review synthesizes the literature from 2000–2025 on rare SCD complications, including atypical neurological events (e.g., spontaneous epidural or subdural hematoma, central retinal artery occlusion, cerebral arteriovenous malformations, posterior reversible encephalopathy syndrome), uncommon hematologic syndromes (acute leukemia, extramedullary hematopoiesis in unusual sites, hemophagocytic lymphohistiocytosis), severe cardiopulmonary emergencies (acute multiorgan failure and fat embolism syndromes), unusual hepatic crises (acute hepatic sequestration, intrahepatic cholestasis), and others (e.g., compartment syndrome). Key insights underscore the need for high clinical suspicion and prompt use of advanced diagnostics (e.g., MRI, specialized laboratory tests) when patients present with atypical or disproportionate symptoms. Clinical implications: Heightening clinician awareness of these rare complications and implementing structured diagnostic strategies can facilitate earlier intervention, improving outcomes and reducing the high morbidity and mortality associated with these infrequent but severe events.

Various therapeutic options are available for the management of Langerhans cell histiocytosis. However, treatment administered to control this disease may be complicated by acute leukemia.