The medical community is familiar with “needle aspiration” of lumps for diagnostic purpose. When one says “needle aspiration” of lumps for diagnostic purpose, automatically it refers to “fine-needle aspiration biopsy.”
Fine-needle aspiration biopsy (FNAB, FNA or NAB), or fine-needle aspiration cytology (FNAC), is a diagnostic procedure used to investigate superficial (just under the skin) lumps or masses. In this technique, a thin, hollow needle is inserted into the mass for sampling of cells that, after being stained, will be examined under a microscope. There could be cytology exam of aspirate (cell specimen evaluation, FNAC) or histological (biopsy – tissue specimen evaluation, FNAB).
In 1986, I embarked on a needle aspiration project, initially involving thyroid nodules and later, breast lumps. I also did aspiration of soft tissue tumors, lymph nodes, and other superficial body tumors. As of December 1988, I have accumulated experience with about a thousand cases of needle aspiration of lumps on the body surface. This experience has convinced me of the usefulness of the ordinary hypodermic needle in evaluating any lump found on the surface of the body. It has also led me to believe that all practicing physicians who are involved in the assessment of body lumps should be familiar with the use of needle in evaluation.
Many papers have been written on needle aspiration of surface lumps but only a few on needle evaluation. Aspiration is just one part of needle evaluation. Feeling the lump with the needle, examining the aspirate on a gross level, and examining the aspirate through a microscope and through other means are the other parts of a needle evaluation. Thus, the phrase “needle evaluation” rather than just “needle aspiration.”
Most clinicians, when they do needle aspiration, do not do gross examination of the non-fluid aspirate obtained. They just wait and rely on the report of the pathologists.
In this post, I will focus on the examining the aspirates on a gross level.
There are two scenarios with respect to examining aspirates on a gross level. One, the aspirate is fluid and the other. the aspirate is not fluid, but substance gotten from a solid tumor.
The color of the fluid aspirate is helpful in the diagnosis of the lump, whether sanguinous or bloody or non-sanguinous or non-bloody. The latter may be any color such as yellow, green, gray, white, etc.
Examples of diagnostic aids based on the color of the fluid aspirate:
Aspirate of colorless gel from a mass on the dorsum of the wrist – ganglion cyst.
Aspirate of purulent material – dirty white, greenish fluid – abscess
Aspirate of brownish or yellowish fluid from a thyroid nodule – colloid cyst.
Aspirate of yellowish or grayish fluid from a breast mass – macrocyst of the breast (part of fibrocystic breast).
Aspirate of milky fluid from a breast mass – galactocoele.
Aspirate of bloody fluid from a breast mass with residual tumor – breast cancer.
If the aspirate is not fluid, one has to get substance from the solid tumor. With experience, one can recognize a pattern for a particular diagnosis, specially, if the tumor is cancer or not.
Below are examples of gross evaluation of non-fluid aspirate
Aspirate from a thyroid nodule – solid, no colloid fluid, whitish bits of substance reflective of a papillary carcinoma.