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Given a neoplasm of uncertain behavior of skin on a patient's face that is suspected to be a basal cell carcinoma, the typical first step is to do a shave biopsy to determine the type of basal cell carcinomas so that one can decide the treatment.

E.g., Medscape (mirror):

A skin biopsy is often required to confirm the diagnosis and determine the histologic subtype of basal cell carcinoma (BCC). Most often, a shave biopsy is all that is required. [Mar 2, 2020]

The downside of a shave biopsy is that it leaves a small scar. Why not use a fine needle aspiration (FNA) biopsy instead to diagnose suspected facial BCCs, since FNA doesn't leave a visible scar and highly accurate for the diagnosis of BCC according to the 2012 study {1}:

We, therefore, recommend this technique for the initial evaluation of a patient with suspected BCC or in cases of recurrence. The technique is cheap, quick, less invasive, and highly accurate for the diagnosis of BCC. The limitation of the technique is low yield in some of the cases.

{1}'s sample size was 37 so I wonder whether other studies contradicted these findings (e.g., showed that the fine needle aspiration (FNA) biopsy wasn't accurate enough to diagnose BCC types). So far I've found {2}, which is a case study (= not high level of evidence) on a recurrent BCC of skin successfully diagnosed through FNA is reported.


References:


I have crossposted the question at:

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  • Kassi et al. (2012) does state that there is low yield in some cases as you pointed out in your quote and was highlighted in the Reddit cross-post Oct 19 '20 at 6:36
  • @ChrisRogers Thanks, the paper says "The limitation of the technique is low yield in some of the cases (5.7%)" so that doesn't seem too bad. That's 2 out of their 37 patient cohort. Oct 19 '20 at 6:40
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Kassi et al. (2012) does state that there is low yield in some cases as you pointed out in your quote and was highlighted in the Reddit cross-post.

Again, pointed out in Reddit, you are sucking up individual cells and not taking a piece of tissue and therefore it can have an incredibly low yield and sometimes produce false negative results.

With the figures on low yield, as you said in the comments, Kassi et al. (2012) points out that:

The limitation of the technique is low yield in some of the cases (5.7%).

You may be correct that this points to 2 out of their 37 patient cohort, however when you consider that about 4.32 million basal cell skin cancers are diagnosed each year in the US alone,

According to one estimate, about 5.4 million basal and squamous cell skin cancers are diagnosed each year in the US (occurring in about 3.3 million Americans, as some people have more than one). About 8 out of 10 of these are basal cell cancers (American Cancer Society, 2020)

that figure of 2 rises to a potential of a much larger number of false negatives.

It is more accurate to look at the structure/organization of the cells via a shave biopsy. An FNA does not allow you do do that. That is why Kassi et al. (2012) only recommends FNA for:

the initial evaluation of a patient with suspected BCC or in cases of recurrence. The technique is cheap, quick, less invasive, and highly accurate for the diagnosis of BCC. However, “cytology does not give much information about tumor patterns or subtypes which can be related to aggressive behavior and can be very important in further therapeutic decisions” [(Vega‐Memije, et al. 2000)]. This should, thus, be followed by “histopathological confirmation before any therapeutic maneuver is considered” [(Vega‐Memije, et al. 2000)]. [emphasis mine].

References

American Cancer Society (2020). Key Statistics for Basal and Squamous Cell Skin Cancers. American Cancer Society. https://www.cancer.org/cancer/basal-and-squamous-cell-skin-cancer/about/key-statistics.html

Kassi, M., Kasi, P. M., Afghan, A. K., Marri, S. M., Kassi, M., & Tareen, I. (2012). The role of fine-needle aspiration cytology in the diagnosis of basal cell carcinoma. Isrn Dermatology, 2012. Open Access https://dx.doi.org/10.5402/2012/132196

Vega‐Memije, E., De Larios, N. M., Waxtein, L. M., & Dominguez‐Soto, L. (2000). Cytodiagnosis of cutaneous basal and squamous cell carcinoma. International journal of dermatology, 39(2), 116-120. https://doi.org/10.1046/j.1365-4362.2000.00893.x

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