Unusual Case of Elevated Alkaline Phosphatase From Chronic Myelomonocytic Leukemia: A Case Report

Abstract

: Serum alkaline phosphatase (ALP) is derived predominantly from the liver and bones. Increased ALP levels reflect diseases of the same. Mostcommon reason of elevated ALP is cholestasis, particularly extrahepatic biliary obstruction. Sometimes increased ALP levels lead to diagnosisof rare diseases. Chronic Myelomonocytic Leukemia (CMML) is a rare malignant hematopoietic stem cell disorder which presents with nonspecific signs and symptoms. CMML presenting with isolated increase levels of ALP is very rare. Here we present a rare case where the patientpresentedwith isolated increased ALP and was found to have CMML. A 78 years old male with no significant liver disease was referredto gastroenterology clinic for isolated increase in ALP. His physical exam was benign. Repeat blood workup showed elevated ALP of 786. Imaging doneshowed hepatosplenomegaly without any biliary dilation or pathology. Liver biopsy confirmed the diagnosis of CMML Discussion ALP is foundin many organs but with unclear function. In liver, it appears to have a rolein downregulating the secretory activities of the intrahepatic biliary epithelium. In Intestine, ALP detoxifies lipopolysaccharide and promotes commensal bacterial colonization of the intestine. In bone, the enzyme is involved with calcification. ALP activity in serum is derived primarily from two sources: liver and bone. Physiological Isolated ALP elevations are usually seen during the 3rdtrimester of pregnancy, DM. Transient elevations are also seen in Infants/toddlers, and in some individuals with blood group O and B. Elevated ALP can be fractioned to confirm the source of origin, butin clinical practice simultaneous elevation of GGT confirms liver to be the cause. After ruling out physiological causes of elevated isolated ALP, next step is to confirm the source of ALP by relevant history, physical examination and checking GGT (Figure 1).2223_A Figure 1. SHOWING STEPWISE APPROACH FOR ISOLATED ELEVATED ALPCMML is a rare clonal bone marrow disorder with a medianage of 66 years and usuallyoverlappingmyelodysplastic/myeloproliferative features. It often presents with nonspecific symptoms fatigue, dyspnea or abdominal fullness CMML patients have a high number of monocytes in their blood. These monocytes can settle in the spleen and cause splenomegalyand usually tend to increase as the disease progresses. Splenomegaly is seenin 32% of patients, buthepatomegaly is uncommon particularly with isolated elevated ALP and is associatedwith poorprognosis.2223_B Figure 2. Involvement of portal tract with mononuclear infiltrate including spindled mast cells