Exercise: Systemic Disease

EXERCISE 6-3. SYSTEMIC DISEASE

6-10. For Case 6-10 (Figure 6-28), which of the following studies would be least useful today?

A.         Chest CT

B.         Left hip x-ray

C.         Bone scan

D.         Skeletal survey

E.         Mammography

6-11. For Case 6-11 (Figure 6-29), what is the next study you should order?

A.   Bone scan

B.   MRI of the knee

C.   Hand films

D.   Chest radiograph

6-12. For Case 6-12 (Figure 6-30), there is no evidence of pneumonia, but there are several abnormalities that are clues to the nature of this patient’s chronic illness. Which finding is such a clue?

A.   The presence of a central venous line

B.   Enlargement of the pulmonary artery segment of the mediastinum

C.   Depression in the endplates of numerous vertebrae

D.   Asymmetry of the breast shadows

6-13. For Case 6-13 (Figure 6-31), which of the following imaging tests is most likely to help determine if this patient has progressive myeloma?

A.         PET-CT

B.         Bone Scan

C.         Chest x-ray

D.         CT of the spine

Radiologic Findings

6-10. D is the correct answer to Question 6-10.

6-11. A thin rim of calcium added to the bony contour of both sides of the right femoral metaphysis (Figure 6-29, arrows) is due to periosteal elevation. Similar findings were present on the left femur and both tib-iae (D is the correct answer to Question 6-11).

6-12. Many vertebral bodies, as best appreciated in the lat-eral view, are shaped like the letter H (arrowheads), with central depressions in the superior and inferior end plates. (Figure 6-30) (C is the correct answer to Question 6-12).

6-13. A is the correct answer to Question 6-13.

Discussion

Case 6-10: Option E, mammography, is a reasonable screen-ing examination. This would be a good test to order for this patient even without new symptoms. Indeed, mammogra-phy should be obtained in any woman of 45 years every year for screening purposes, irrespective of her history. Bone scans are also often ordered as screens for metastatic diseasein asymptomatic breast cancer patients, particularly for the first 2 to 3 years after diagnosis. Because this patient is com-plaining of skeletal pain, both a bone scan (Figure 6-32 A) and conventional radiographs of the affected area (Figure 6-32 B) are indicated. A chest CT can be helpful to find small pulmonary metastases that may not be apparent on a conventional chest radiograph. Whether to order it for this woman may depend in part on the preferences of the attend-ing oncologist and on risk factors such as the size of the orig-inal tumor and nodal status at the time of diagnosis. Option D, a skeletal survey, is inappropriate. Bone surveys are gener-ally utilized in breast cancer only for follow-up of patients with widespread osseous metastatic disease.

In this patient’s case, a bone scan revealed multiple areas of abnormally increased accumulation of radionuclide, includ-ing the left acetabulum (Figure 6-32 A,B). The multiplicity of lesions, together with the history of breast cancer (which often metastasizes to bone and may do so after a disease-free inter-val of many years), is very suggestive of metastatic disease. Some oncologists would choose to treat the patient for pre-sumed metastatic disease on the basis of the bone scan, his-tory, and current symptoms. Others would prefer a biopsy before proceeding to further treatment. This patient under-went a CT-guided needle aspiration of the acetabular lesion, which revealed metastatic tumor (Figure 6-32 C). To evaluate for possible impending pathologic fracture (Figure 6-33), most oncologists would also request conventional radi-ographs of areas demonstrating increased activity on the bone scan, particularly those in weight-bearing bones.

Case 6-11: Periosteal elevation is a nonspecific finding that occurs with local disorders such as fracture, bone tu-mors, and osteomyelitis and also with systemic or multifocal disorders such as bone infarction (Figure 6-34), venous sta-sis, and secondary hypertrophic osteoarthropathy. Because this finding is bilateral, it is more likely due to a systemic or multifocal disorder than to a local one.

Of all systemic disorders that may be associated with pe-riosteal new bone formation, secondary hypertrophic os-teoarthropathy is the most important to exclude. At one time it was called hypertrophic pulmonary osteoarthropathy be-cause it is usually caused by pulmonary disease. The designa-tion secondary hypertrophic osteoarthropathy reflects current understanding that this disorder may also be due to nonpulmonary diseases such as inflammatory bowel disease or congenital cardiac anomalies. Nonetheless, pulmonary disease, specifically lung cancer, remains the most common cause. This patient, in fact, had lung cancer (Figure 6-35).

A bone scan could be useful if you did not notice the pe-riosteal new bone or were not sure of its presence. Hand films could demonstrate clubbing, which may be seen with some of the same disorders that cause hypertrophic osteoarthropathy, but simple physical inspection of the patient’s hands would accomplish the same thing. MRI of the knees will not be helpful in this case.

Case 6-12: This patient (see Figure 6-30) has sickle cell disease. The peculiar shape of multiple vertebral bodies is very characteristic of sickle cell anemia, though it may occa-sionally be seen in other diseases affecting the marrow cavity, particularly Gaucher’s disease. It may be caused by infarction of bone beneath the endplates, with remodeling of the cortex to produce the H-shape.

When red cells sickle, they clump together and may block blood vessels. In bone this leads to avascular necrosis, which may be widespread, involving many bones simultaneously. The mottled appearance of this patient’s humeral heads is due to avascular necrosis and is a common finding in patients with sickle cell anemia.

Though they were not included among the possible answers to the question, there are other findings on this examination that are clues to the diagnosis. The gas-filled splenic flexure of the colon occupies too much of the left upper quadrant on the frontal view. There is no room for a spleen of normal size. In sickle cell patients, the spleen is often infarcted so that by any time they reach adulthood, it has shrunk to a small fraction of normal size. People with sickle cell disease are prone to early de-velopment of calcium bilirubinate gallstones (cholelithiasis).

Modest enlargement of the pulmonary artery, as seen in this patient, is so common in young women that it is consid-ered normal in that population. The central line may be seen in many patients with a variety of disorders requiring chronic intravenous therapy.

Case 6-13: Multiple myeloma is a disease that can never really be considered cured. The goals of therapy are control ofsymptoms and, if possible, induction of remission. Remis-sion may last months or even years, and during remission the patient is monitored for any signs that the disease has re-turned and is progressing. In this patient’s case, the oncolo-gists are looking for any imaging-based evidence of disease progression to back up a fairly weak clinical indicator.

A challenge is that the patient is already known to have lytic bone disease. Even though the myeloma has been in re-mission, the lytic lesions will not have gone away. Therefore, imaging studies that rely primarily on anatomy will only be helpful if they unequivocally show evidence of new lytic le-sions. The bone survey has already been asserted to be un-changed, so no other conventional radiographs are likely to be helpful, either. Therefore, a chest x-ray will not be a good choice. CT scans are also anatomically based tests and can be expected to show lytic lesions without necessarily helping to determine if the lesions are old and quiescent or if they are actively growing.

What is needed is a test that will assess the metabolic ac-tivity of this patient’s multiple myeloma, preferably with some associated anatomic information. MRI may be helpful in such situations. It is a good anatomic test, and if contrast is given, it also demonstrates areas of hyperemia. MRI, how-ever, was not one of the answer choices. Bone scans are meta-bolic tests, but myeloma is a notorious source of false negative bone scans.

PET-CT may be quite useful for differentiating quies-cent from metabolically active, growing lesions of myeloma (Figure 6-36).