Introduction

Chronic Lymphocytic Leukemia (CLL) is the most common lymphoproliferative disease and affects the older people. It is characterised by uncontrolled proliferation and accumulation of mature B lymphocytes. In most cases, it is asymptomatic. Symptoms can occur secondary to bone marrow infiltration. The spleen, lymph nodes, liver and bone marrow are primarily involved. A second malignancy may be encountered in a patient with CLL. There are reports of spread of CLL to the leptomeninges, gastro-intestinal tract, prostrate and intervertebral disc(1,2,3,4,). CLL seldom involves the bone and may present with areas of osteopenias (2). A report of presentation of CLL as a pyogenic arthritis of the proximal interphalangeal joint exists (5). A literature search brought forth a single case of spread of CLL to the bone (6). However , there are no previous reports of metastasis of CLL to the proximal femur.

Case Report

We present a case of a seventy two years old gentleman, who presented to us with a low backache. Blood investigations followed by the haematologist’s opinion confirmed a CLL (Rai stage 0 ). MRI of the spine aroused a suspicion of leukemic infiltration of T9 vertebra. A spinal biopsy revealed a normal histology. A trephine biopsy from the iliac crest confirmed a CLL. A search for a primary in other organs was futile. With analgesia, the pain improved and the patient continued to walk with a stick. He was reluctant to investigate further and returned to work. Eight months later he was admitted with excruciating lower back pain restricting him to his bed. He felt better with analgesia and bed rest. Unfortunately, during his stay in the hospital, he had sudden onset of sharp pain in his right thigh. Radiograph revealed a pathological subtrochanteric fracture of his right femur with evidence of metastasis (Fig 1). The opposite femur radiograph also exhibited similar changes without a fracture(Fig 2). The subtrochanteric fracture in the right femur was fixed with a long gamma nail(Fig 3) . The opposite femur was also fixed with a long gamma nail as a prophylaxis(Fig 3). The reamings from the subtrochanteric fracture were sent for histological study.

To our surprise, the histological analysis revealed a B cell chronic lymphatic leukaemia.

Figure 1

Fig 1 Radiograph of pathological fracture of proximal femur

Figure 2

Fig 2 Radiograph showing lytic changes in the left femur

Figure 3

Fig 3 Radiograph after fixation

Discussion

Backache is a common problem in the population. It should not be ignored until investigated fully. A critical examination of the hips should be a mandatory part of every back examination. Something more sinister may present in the disguise of a backache. Unless we are careful, it may easily be missed. Metastasis of CLL to the bone is extremely rare. As it is so uncommon , it may not be diagnosed and may go unreported .Early diagnosis and immediate action may reduce the morbidity associated with pathological fracture . Histology is essential for diagnosis. This is probably the second case of CLL metastasis to the bone and the first one to metastasize to the proximal femur. To our knowledge this is the first published case of spread of CLL to the proximal femur. Awareness of its presence is vital to the prevention of associated morbidity.