Preoperative Coagulopathy as a Diagnostic Clue to Lupus Anticoagulant Associated with Hidden Marginal Zone Lymphoma: A Case Report

In the human body, blood performs a delicate balancing act. It must flow freely to nourish tissues, yet clot quickly enough to stop bleeding when a vessel is cut. Doctors rely on laboratory tests to measure how well this system is working. Two of the most common checks are the prothrombin time and the partial thromboplastin time. These tests measure how many seconds it takes for a blood sample to form a clot. Under normal circumstances, these numbers fall within a predictable range. When they are too high, it usually means the blood is taking too long to clot, which could signal a missing ingredient in the blood's clotting machinery or the presence of a substance that is interfering with the process. Sometimes, the cause of these delays is not a simple deficiency but an antibody, a protein the immune system makes to fight off threats, that mistakenly targets the blood's own clotting factors. This specific type of interference is known as a lupus anticoagulant. While the name suggests a link to lupus, an autoimmune disease, this antibody can appear in people without that condition, often as a sign of an underlying issue that has not yet been discovered.

This story begins with a routine medical visit that took an unexpected turn. A sixty-three-year-old woman, who had well-controlled hypertension and type 2 diabetes but no history of serious complications, arrived at a clinic to schedule cataract surgery for her right eye. Before any operation can proceed, doctors run a standard battery of blood tests to ensure the patient is safe for anesthesia and surgery. For this woman, the results were alarming. Her prothrombin time was slightly elevated at 12.8 seconds, but her partial thromboplastin time was drastically high at 102 seconds, more than double the upper limit of what is considered normal. The surgical team immediately cancelled the procedure. The patient had no history of bleeding problems, and her past surgeries, including a C-section and a gallbladder removal, had gone smoothly. Yet, her blood was behaving as if it were incapable of clotting properly.

The medical team began a careful investigation to find the source of the delay. They looked at her overall health and found she was pale and tired, with a white blood cell count that was significantly higher than normal. She also reported night sweats, a loss of appetite, and a weight loss of more than ten percent over six months. A physical examination revealed a massive enlargement of her spleen, an organ located in the upper left abdomen that filters blood. A scan confirmed the spleen was enormous, measuring 16 by 11 by 26.7 centimeters, but showed no other unusual growths in her body. The doctors needed to understand why her blood was taking so long to clot. They performed a mixing study, a test where the patient's blood is combined with normal blood. If the delay were caused by a missing clotting factor, the normal blood would have fixed the problem, and the time would have returned to normal. Instead, the time remained long. This result indicated that something in the patient's blood was actively blocking the clotting process, rather than simply lacking a necessary component.

Further testing revealed the culprit: a lupus anticoagulant. This is an antibody that interferes with the chemical reactions needed for blood to clot, causing the laboratory tests to show a long delay, even though the patient is not actually bleeding. The test results showed a ratio of 2.43, a number that confirmed the presence of this antibody was strong and definite. The doctors also checked for other common causes of long clotting times, such as deficiencies in specific clotting proteins, but those levels were normal. The presence of this antibody, combined with the enlarged spleen and the high number of white blood cells, pointed toward a hidden cancer. A biopsy of the bone marrow, the spongy tissue inside bones where blood cells are made, showed a dense collection of abnormal cells. These cells were identified as a type of slow-growing cancer called marginal zone lymphoma, a disease that originates in the immune system's B cells.

The connection between the cancer and the blood disorder was the key to the patient's treatment. The doctors determined that the lymphoma was driving the production of the lupus anticoagulant, a rare occurrence where a tumor causes the immune system to create these interfering antibodies. The patient began a chemotherapy regimen that included a drug called rituximab, along with vincristine and cyclophosphamide. This treatment targeted the cancer cells directly. After three cycles of chemotherapy, the cancer went into remission, and the patient's blood tests returned to normal. The lupus anticoagulant disappeared, and her clotting times became normal again, allowing her to eventually undergo her cataract surgery without issue.

This case highlights a critical lesson for medical practice: unusual blood test results can sometimes be the first and only sign of a hidden cancer. While marginal zone lymphoma typically presents with swollen lymph nodes or other visible symptoms, this patient showed none of those classic signs. Instead, the disease revealed itself through a laboratory anomaly that initially seemed unrelated to cancer. The study suggests that when a patient has unexplained delays in blood clotting, especially when mixing tests show an inhibitor rather than a deficiency, doctors should consider the possibility of an underlying malignancy. Treating the cancer resolved the blood disorder, proving that the antibody was a consequence of the disease rather than a separate condition. This finding underscores the importance of looking beyond the immediate symptom to find the root cause, ensuring that patients receive the correct treatment for the condition that is actually driving their illness.