Sarcoidosis cases involved lung, cervical, mediastinal, and abdominal nodes, as well as the bowel, adrenal gland, and pleura in 32 patients.
"It is evident that many nodes with known malignancy can be misinterpreted, along with the existing inflammatory and infective pathology," said lead author Dr. Sikandar Shaikh from Yashoda Hospital and Shadan Medical College. "With this study, we can focus on the imaging criteria of CT, PET, and PET/CT, which will help in better evaluation of false-negative and false-positive results pertaining to the characteristics of nodes on CT and maximum standardized uptake values [SUVmax] on PET."
Among the findings, sarcoidosis caused false-positive readings in nine of 11 staging cases, leading to overstaging; in 12 of 14 restaging cases; and in seven patients with no malignancy. Four patients were erroneously considered to have lung cancer and three were thought to have an abdominal malignancy.
The researchers were able to establish SUVmax parameters for staging. In staging PET/CT, the mean SUVmax of the primary tumor was 5.0 (± 3.6), while the SUVmax of sarcoidosis to determine metastasis was 4.5 (± 2.4) in the lung and 5.6 (± 3.3) in the lymph node. The mean SUVmax of sarcoidosis mimicking malignancy was 3.7 (± 1.3) in the lung and 6.1 (± 3.3) in the abdomen.
"Thus, we are able to differentiate between the sarcoidosis and malignant nodes," Shaikh said. "This is possible with results as described in this study. However, more evaluations have to be done to get better sensitivity and specificity."
Shaikh and colleagues plans to extend their research to related areas, such as tuberculosis and other tropical diseases in India.
