From the Guidelines
Yes, a biopsy is generally recommended for a cystic mass to determine its nature and rule out malignancy. The approach to biopsy depends on the location and accessibility of the cyst, as well as the patient's overall health. Fine-needle aspiration (FNA) or core needle biopsy (CNB) are common methods used, as seen in studies 1, 2. In some cases, surgical excision or drainage may be necessary. It's essential to evaluate the cyst's characteristics, such as size, location, and symptoms, to guide the decision for biopsy. Imaging studies like ultrasound or MRI may be used to guide the biopsy procedure, as recommended by guidelines 3, 4.
- For complex cystic and solid masses, a tissue (core needle) biopsy is recommended, as the risk of malignancy is relatively high, around 14% and 23% in some studies 2.
- If the cyst is classified as a complicated (BI-RADS category 3) nonsimple cyst, options include aspiration or short-term follow-up with physical examination and ultrasound with or without mammography every 6 to 12 months for 1 to 2 years to assess stability, as outlined in guidelines 1, 3.
- A biopsy should be performed for a complicated cyst that increases in size on follow-up, and if the mass recurs after aspiration, or the nonsimple cyst is classified as complex on ultrasound (i.e., BI-RADS category 4), then ultrasound with image-guided biopsy or surgical excision is warranted 1, 3.
- For patients with a neck mass deemed at increased risk for malignancy, clinicians should continue evaluation of patients with a cystic neck mass, as determined by FNA or imaging studies, until a diagnosis is obtained and should not assume the mass is benign, as stated in guidelines 5, 4, 6.
From the Research
Biopsy for Cystic Masses
- The decision to perform a biopsy on a cystic mass depends on various factors, including the size, location, and characteristics of the mass, as well as the patient's overall health and medical history 7, 8, 9, 10, 11.
- For cystic pancreatic lesions, annual imaging surveillance is generally sufficient for benign serous cystadenomas smaller than 4 cm and for asymptomatic lesions, while lesions with more complex features or with growth rates greater than 1 cm/year should be followed more closely or recommended for resection if the patient's condition allows surgery 7.
- For indeterminate renal cystic masses (Bosniak 2F and 3), CT-guided biopsy can be used to differentiate malignancies from benign lesions, with a sensitivity of 0.71 for malignancies and 0.91 for benign complex cysts 8.
- Imaging-guided biopsy can also be useful in identifying nonmalignant lesions in complex cystic renal masses and avoiding unnecessary surgery in 39% of patients 9.
- For palpable breast masses, fine-needle aspiration is a fast, inexpensive, and accurate method for differentiating solid and cystic masses, while core-needle biopsy allows for histologic diagnosis and hormone-receptor testing 10.
- Fine-needle aspiration biopsy of the kidney has a traditionally well-defined role in the diagnosis and treatment of renal lesions, with a high degree of accuracy in diagnosing malignant lesions and benign cysts 11.
Diagnostic Considerations
- The diagnostic approach to cystic masses should take into account the patient's age, medical history, and the characteristics of the mass, as well as the potential risks and benefits of biopsy 7, 8, 9, 10, 11.
- Cystic lesions with suspicious cytologic patterns or complex features should be further evaluated with imaging-guided biopsy or other diagnostic techniques to determine the presence of malignancy 8, 9, 11.
- The use of imaging-guided biopsy can help to avoid unnecessary surgery and reduce the risk of complications associated with surgical intervention 8, 9.