Aspiration of cysts and bursae

See also: 'Minor Surgery' > Best Treatment > Therapeutic skills > Aspirations of cysts and bursae

Aspiration of cysts/bursae is one of the simplest procedures offered as minor surgery services. Types of lesions suitable for aspiration include breast cysts, hydrocele, spermatocele and epididymal cysts, thyroid cysts, an olecranon bursa, prepatellar bursitis (‘housemaid’s knee’), but not a semimembranosus bursa (Baker’s cyst).

Breast cyst

The most common breast masses are those caused by benign breast disorders and conditions – i.e. cysts, fibrocystic disease, fibroadenoma, and intraductal papilloma. All should be evaluated for potential malignancy.

Breast cysts commonly present in pre- and perimenopausal women (aged >40 years), and regress after menopause (Borgen PI, Hill ADK (eds), 2000) . Therefore their etiology may be related to the changes in the overall hormone profile of the patient.

There are two main varieties of the cysts in the breast (Bull MJV, Gardiner P, 1995) :

1. Simple retention cysts (galactocele) – associated with blockage of the lactiferous duct system), and often occurring during or following lactaction and breastfeeding,
2. Cyst formation in benign new growth tissue (e.g. fibroadenoma).

Cysts are usually firm, mobile, and smooth or regular in shape, may change in size relative to the menstrual cycle and are most evident just before menstruation. They are often associated with the duct system and can occur almost anywhere in the breast (Bull MJV, Gardiner P, 1995) . They can be single or multiple, unilateral or bilateral, symptomatic (e.g. painful) or detected on mammographic screening (usually as well-defined soft-tissue densities – Fig. 1A) (Borgen PI, Hill ADK (eds), 2000) . Their most frequent localization is the upper outer quadrant of the breast. Many of these isolated breast swellings prove to contain fluid when diagnostic aspiration is attempted. Ultrasound is the mainstay of diagnosis and is extremely reliable in distinguishing solid from cystic masses as well as between a simple and a complex cyst (i.e. a cyst with intramural nodules like papillomas, intracystic carcinoma or carcinoma adjacent to a cyst). Simple cysts appear as well-defined, anechoic, thin-walled lesions (Fig. 1B). Any complex cyst requires US-guided aspiration and cytological examination of its contents (Borgen PI, Hill ADK (eds), 2000) .

1. Mammography (left, oblique view): well-defined, round-shaped, homogenous soft tissue density lesions (arrows), surrounded by a transparent halo are depicted. Pneumocystography (right): aspiration of the cyst followed by air injection revealed the smooth inner surface; no intraluminal lesion is depicted (arrow).
2. Ultrasound examination: a well-defined, echo-free cyst of 3 cm in diameter is visible (left image, arrow). Following aspiration (right image) the cyst became shrinked and irregular (arrow). [Courtesy of Prof. András Palkó, Department of Radiology, University of Szeged, Hungary].

Needle aspiration of the mass will eventually determine whether or not fluid is present. A solid lump may be lumpy breast tissue, a fibroadenoma or breast cancer. A cyst will disappear as it is aspirated, giving also an immediate diagnosis (Goldberg A, Stansby G (eds), 2005) .
The amount of fluid may vary, so its colour (most often greenish brown). Bloodstaining of the fluid is a sign that the so-called ‘cyst’ may not be benign (Cracknell ID, Mead MG, 1997) . Aspiration of the cyst to dryness is the treatment of choice (Borgen PI, Hill ADK (eds), 2000) . Simple aspiration will usually be sufficient to cure of the disease. Repeated aspiration of breast cysts is also a safe procedure provided that the lump disappears completely and no malignant cells are found on cytological examination. The relationship between cysts and breast cancer risk is controversial. If the mass does not disappear completely following aspiration, or if the fluid is uniformly blood stained, the fluid should be sent for cytology, and a biopsy must be performed (Borgen PI, Hill ADK (eds), 2000) . If a cyst is aspirated, the patient is asked to return for a re-examination in 6-8 weeks. If the mass (known to be a simple cyst by US) has recurred, it may be aspirated once more, but after the second recurrence excision is warranted. Cysts in postmenopausal women should be excised since they may herald an intracystic carcinoma (Borgen PI, Hill ADK (eds), 2000) .

Indications and contraindications for breast cyst aspiration as well as potential complications are identical with those describedelsewhere [see"Percutaneous fine-needle aspiration biopsy"].

An enlarged testicle should be considered a tumour unless this is ruled out (Kunnamo I (ed), 2005) . If the swelling is located outside the testicle, it may be a hydrocele, a spermatocele or epididymal cyst, a varicocele or an inguinal hernia.

Hydrocele, spermatocele and epididymal cysts

Hydrocele is a common scrotal swelling caused by a collection of fluid inside the tunica vaginalis surrounding the testicle and appendix testis (Bull MJV, Gardiner P, 1995) ^, (Kunnamo I (ed), 2005) . It gradually enlarges and may contain as much as a litre of fluid. Hydrocele usually presents as a painless cystic mass that transilluminates during an examination with the use of a powerful torch in a darkened room (Fig. 2B). It can be freely deformed unlike a solid tumour (Kunnamo I (ed), 2005) . Ultrasonography is very helpful in diagnosis. It should be noted that hydrocele may complicate testicular tumour.

The testicular enlargement caused by collection of fluid in space around the testis (1), which allows for the passage of light (transillumination, 2).
[Reproduced, with permission, from: http://medicine.ucsd.edu/clinicalimg (Catalog of Clinical Images by Dr. Charles Goldberg, MD; © Regents of the University of California)]

A small hydrocele need not be treated. A large one can be treated surgically or with sclerotherapy. Needle aspiration is rarely performed and it is not beneficial as the fluid collection recurs (Kunnamo I (ed), 2005) . Before proceeding, an operator should ensure that he/she is dealing with a hydrocele and not a scrotal hernia (which does not transilluminate and often can be reduced into the inguinal canal), cystic or solid tumour, traumatic haematocele or varicocele (Cracknell ID, Mead MG, 1997) . After disinfection of the scrotal skin, the needle is inserted at the lowest point in the scrotum that shows transillumination (Cracknell ID, Mead MG, 1997) . Aspiration yields clear fluid.

Spermatocele occurs as a round, soft and asymptomatic mass separate from and superior to the testicle. It transilluminates fairly well (Kunnamo I (ed), 2005) . Ultrasonography is also helpful in diagnosis. Spermatoceles can be treated in the same way as hydrocele – by aspiration as described above, although fluid volumes are smaller (Cracknell ID, Mead MG, 1997) . Aspiration of the contents may be diagnostic and reveals white cloudy or grey fluid with immotile sperm. Large spermatocele can be treated surgically (Kunnamo I (ed), 2005) .

Epididymal cysts are benign, often solitary cystic fluid collections commonly seen during urological or ultrasound testicular examinations. They present as painless testicular enlargements on palpation and are echo-free at ultrasound examination. A cyst of the epididymis is, in fact, a spermatocele arising from the head of the epididymis (Bull MJV, Gardiner P, 1995) . In this case, the swelling transilluminates and lies above and behind the testis. Epididymal cysts are treated only if symptomatic. Surgery is the standard treatment, although it carries a high risk of complications. Percutaneous sclerotherapy with the use of polidocanol or aspiration have gained wide acceptance as a valid therapeutic alternatives to surgery in the management of these cysts.

The technique of aspiration of a epididymal cyst is as for a breast cyst (Cracknell ID, Mead MG, 1997) . Always it should be checked whether the cyst transilluminates – if it does not, an aspiration should not be attempted. Small epididymal cysts rarely cause symptoms and therefore may not be aspirated. In case of multiple cysts, referral to a consultant surgeon may be necessary.

Thyroid cyst

Thyroid cysts may present as a lump or may cause pressure symptoms or even local pain (e.g. if bleeding into the cyst occurs). The most important is to rule out malignancy (Goldberg A, Stansby G (eds), 2005) . A cystic nodule may, however, be malignant or a carcinoma may grow on the cyst wall (Kunnamo I (ed), 2005) .

[Reproduced, with permission, from: http://medicine.ucsd.edu/clinicalimg (Catalog of Clinical Images by Dr. Charles Goldberg, MD; © Regents of the University of California)]

A thyroid cyst can be aspirated in the same way as for breast cysts. Before proceeding, ultrasound can be helpful in determining the diagnosis, if it is in doubt.
A cyst with a diameter < 4 cm should be aspirated during ultrasound examination (Kunnamo I (ed), 2005) . A fine-needle aspiration may be all that is required to show this is a simple cyst. Nevertheless, the aspirated fluid should be sent for cytology (Goldberg A, Stansby G (eds), 2005) . Bleeding and haematoma formation are the most common complications (Cracknell ID, Mead MG, 1997) . A cyst with a diameter > 4 cm should be removed surgically (Kunnamo I (ed), 2005) . Cysts may also require excision if cytology dictates (i.e. cytological finding is class III) or if they recur (Goldberg A, Stansby G (eds), 2005) . Follow-up examination is always indicated.

Bursitis

Bursitis is inflammation of the synovial cavities that surround joints, allowing free movement of soft tissue periarticular structures. This condition may be due to infection (e.g. most commonly in the olecranon bursa), direct trauma, friction or repetitive pressure (such as leaning on the elbows – ‘miner’s or student’s elbow’ or olecranon bursitis, or in a job requiring kneeling – ‘housemaid’s knee’ or prepatellar bursitis), or may be idiopathic. Clinical findings include: pain, tenderness, and swelling of the involved bursa. Bursae should be aspirated for diagnosis and treatment. Septic bursitis requires immediate antibacterial treatment.

Olecranon bursitis

The olecranon bursa is a true bursa, consisting of a fibrous capsule with a synovial lining. It forms a protective cushion over the elbow and normally contains only the minimal amount of synovial fluid (Bull MJV, Gardiner P, 1995) . Olecranon bursitis can result from the factors listed above as well as from systemic inflammatory processes (e.g. rheumatoid arthritis or gout). The bursa becomes distended with a serous fluid (Fig. 4). The elbow may be surprisingly pain-free. Pain with motion usually occurs past 90 degrees of flexion. Aspiration of the swollen bursa reveals bland, clear synovial fluid. Acute trauma may result in haemorrhagic bursitis which may also be aspirated. Locally injected corticosteroids are useful in treatment of aseptic bursitis.

Note swelling of the left olecranon bursa (1), comparing to the patient’s right elbow which is normal (2). [Reproduced, with permission, from: http://medicine.ucsd.edu/clinicalimg (Catalog of Clinical Images by Dr. Charles Goldberg, MD; © Regents of the University of California)]

Clinical scenario

(Choudaray V., 2004)

A 45-year old labourer presents to the Emergency Department with a one day history of pain and swelling over his right elbow. Examination reveals a generally well, apyrexial man with a swollen, warm right olecranon bursa with overlying redness (Fig. 5A). You wonder whether it is necessary to aspirate and analyse bursal fluid to diagnose and treat this patient.

Septic olecranon bursitis is a relatively common problem and should be suspected if the bursa region has become swollen, painful, red and hot (Fig. 5A), or if the patient has fever (Kunnamo I (ed), 2005) . It is usually due to Staphylococcus aureus and should be initially treated with antibiotics after a sample for bacterial culture has been taken. In septic bursitis the sample is often slightly bloody and reddish (Kunnamo I (ed), 2005) . Pyogenic bursitis may also require incision and drainage whenever an abscess-like collection of pus is present.

Note swelling and redness of the olecranon bursa in picture on left due to bacterial infection (1), comparing to the patient’s elbow on right which is normal (2). [Reproduced, with permission, from: http://medicine.ucsd.edu/clinicalimg (Catalog of Clinical Images by Dr. Charles Goldberg, MD; © Regents of the University of California)]

Prepatellar bursitis

There are several bursae in the region of the knee, representing synovial compartments that are separate from the knee joint itself, and located over bony prominences and at areas of friction between tendons (e.g. anserine bursitis occurs with inflammation of the bursa on the medial side of the proximal tibia; there is localized tenderness and swelling over the knee). Bursitis in this area most commonly affects the prepatellar and infrapatellar bursae.

The prepatellar bursa is a superficial bursa with a thin synovial lining located between the skin and the patella ('kneecap'). Normally, it does not communicate with the joint space and contains only a minimal amount of fluid, but in the course of inflammation there is a marked increase of fluid within its space (Allen KL, Fried GW) .

Two cases (1, 2) presenting with a typical swelling and redness of the left prepatellar bursa. [Reproduced, with permission, from: http://medicine.ucsd.edu/clinicalimg (Catalog of Clinical Images by Dr. Charles Goldberg, MD; © Regents of the University of California)]

Aseptic prepatellar bursitis rarely requires aspiration of the bursa fluid, but it should always be done under strictly sterile conditions. Exactly the same principles apply as with an olecranon bursa (Cracknell ID, Mead MG, 1997) . The fluid should be sent to the laboratory for further analysis (including a Gram stain and culture of an aspirate to rule out infection, and an examination of the fluid under polarized light to detect the presence of crystals suggesting gouty arthritis or pseudogout). There is also the need for firm bandaging of the knee after aspiration, and the absolute rule to inject the 40 mg of methylprednisolone into the site, provided that the fluid withdrawn is clear, with no evidence of infection (Cracknell ID, Mead MG, 1997) . Septic prepatellar bursitis usually occurs from breaks in the overlying skin or puncture wounds (Fig. 7). Staphylococcus aureus is the most common pathogen involved. This condition requires antibiotic therapy. Repeated aspiration of the inflamed fluid as well as surgical drainage and bursectomy may be required.

Swelling and redness of the prepatellar bursa caused by bacterial infection. Inflammation and oedema have led to desquamation. [Reproduced, with permission, from: http://medicine.ucsd.edu/clinicalimg (Catalog of Clinical Images by Dr. Charles Goldberg, MD; © Regents of the University of California)]

The infrapatellar bursa can be divided into superficial and deep components. The superficial component lies between the patellar ligament and the skin, while the deep component lies between the patellar ligament and the proximal anterior tibia (Chang E, Talbot-Stern J) . Superficial infrapatellar bursitis is caused by a similar mechanism as prepatellar bursitis, with the symptoms located slightly inferior to the prepatellar bursa (Fig. 8). It is commonly seen in people frequently kneeling in an upright position (hence the name ‘clergyman knee’). The deep infrapatellar bursa is less frequently inflamed.

Clinically, the patient exhibits pain with flexion and extension at the extremes of the range of motion. Oedema is located on both sides of the patellar tendon and is tender (Chang E, Talbot-Stern J) .

Swelling and redness of the left infrapatellar bursa. [Reproduced, with permission, from: http://medicine.ucsd.edu/clinicalimg (Catalog of Clinical Images by Dr. Charles Goldberg, MD; © Regents of the University of California)]

Semimembranosus bursa (Baker’s cyst, popliteal cyst)

Baker’s cyst represents a diverticulum of the synovial sac that protrudes through the joint capsule of the knee. It can occur as a large and tense popliteal swelling caused by knee joint fluid protruding to the back of the knee (see Fig. 9). It can be congenital in children or in adults secondary to injury, arthritis (e.g. as a complication of rheumatoid arthritis) or osteoarthritis (Kunnamo I (ed), 2005) . This is invariably in connection with the knee joint, and usually loculated, making aspiration impossible (Bull MJV, Gardiner P, 1995) .

Ultrasound examination: An irregular, sharp-edged echo-poor lesion with a diameter of 6 cm is visible in the popliteal region (arrows) with an echogenic septum in its central part. [Courtesy of Prof. András Palkó, Department of Radiology, University of Szeged, Hungary].

In children, if a large cyst does not recede spontaneously, it can be removed surgically. In adults, the cyst can be aspirated, avoiding puncture of vessels. Following drainage, methylprednisolone or triamcinolone may be instilled using the same needle (Kunnamo I (ed), 2005) .
Although aspiration of this bursa can be very tempting, recurrence is common as more fluid quickly replaces any amount removed. As a consequence, an operation may be necessary (consisting in the removal of the synovium that leads to the cyst formation). Also bleeding (usually from the popliteal artery) is a particular risk here (Cracknell ID, Mead MG, 1997) (see Fig. 1B in the section on Arthrocentesis ).