Complex cystic and solid breast mass

A complex cystic and solid breast mass also knowns as a complex breast cyst is a morphological type of breast cyst along with simple breast cysts and complicated breast cysts. Complex breast cysts are defined as cysts with thick walls, thick septa, intracystic masses, or other discrete solid components.

Terminology

The currently preferred term for complex breast cysts is complex cystic and solid mass to avoid confusion with a complicated cyst. ⁹

Epidemiology

Breast cysts are extremely common and are present in most women over 40 years old. Breast ultrasound allows its detection and the correct diagnosis of cyst has been reported to be almost 100%.

5% of breast ultrasound examinations report complex cyst.⁷

Complex breast cysts have a malignancy rate of 0.3% among breast neoplasms, it still has had a substantial probability of being malignant (23% and 31% in 2 series). ⁷

Pathology

Complex breast cysts are associated with a variety of benign, atypical, and malignant pathological diagnoses, including fibrocystic changes, intraductal papilloma, abscess, hematoma, fat necrosis, fibrocystic mastopathy, phyllodes tumor, papilloma atypical ductal hyperplasia (ADH), ductal carcinoma in situ (DCIS), and infiltrating ductal carcinoma.  ⁸

Radiographic features

Breast ultrasound

The presence of a thick wall, thick septae, or intracystic mass is characteristic of complex breast cysts ². The majority show posterior acoustic enhancement due to the cystic component ⁵. The margin may be macro- or microlobulated, indistinct, or even irregular.

Depending on the ultrasonographic appearance complex breast cysts can be categorized into four categories using criteria adapted from Berg et al:

type I, masses with a thick wall (>0.5 mm) or thick septa (>0.5 mm) PPV for malignancy 7.1% ⁸

type II, masses of an intracystic type with one or more discrete solid mural lesions within a cyst PPV for malignancy 16.7%

 type III, masses containing mixed cystic and solid components with the cystic portion occupying at least 50% of the mass PPV for malignancy 61.1%

type IV, masses that were predominantly (at least 50%) solid with eccentric or central cystic foci PPV for malignancy 44.8% ⁸

Radiology report

At ultrasound, breast cysts are categorized as simple, complicated, or complex. Appropriate categorization is important because the management of each type differs.

Studies have demonstrated the importance of appropriate categorization of complex breast cysts by using Berg criteria and describe other sonographic findings such as lesion size greater than or equal to 2 cm, the absence of circumscribed margins, RI greater than or equal to 0.7, and axillary abnormal nodes are significant predictors of malignancy. ⁸

Treatment and prognosis

Some authors find that the complex cystic lesions have 23% up to 31% risk of malignancy ⁴, while others estimate the risk as 0.3% ⁴. The former consider the complex breast cyst as intermediate BIRADS IVb lesions, while the latter consider them to be BIRADS IVa lesions ⁴.

The decision whether any interventional technique should be therefore guided by a clear indication and should be compatible with the patient's history and the result of mammography ⁴. The radiologist should choose the appropriate measure from the following alternatives:

• close monitoring

• sampling

• fine-needle aspiration (FNA)

  • FNA is the first interventional procedure that should be performed when there it is difficult to differentiate between a complicated cyst and a predominantly cystic complex mass
  • purulent fluid suggests an inflammatory lesion and should be assessed by microbiological analysis, while hemorrhagic fluid raises the possibility of malignancy and should be analyzed cytologically
  • assessing the lesion after aspiration is important to depict the solid component. if a solid component remains, core biopsy should be performed in the same session ⁴

• biopsy

  • core biopsy should be the first intervention if there is a proven solid component associated with a suspicious finding in the mammogram (e.g. micro-calcification or architectural distortion) ⁴

Practical points

Moving the patient to decubitus position is useful to differentiate the solid masses from thick debris ⁴. If the echogenic component is mobile it represents debris, pus, or a clot. If the echogenic component is immobile, it may represent either a true intracystic mass or debris adherent to the cyst wall.