ABSTRACT

Background

Plantar corns are a cause of pain and activity restriction. Debridement may give temporary relief of symptoms but a surgical excision may be sought by patients looking for a curative treatment. The following study reviews the effectiveness of surgical excision and the histopathological diagnosis of skin lesions which were clinically diagnosed as corns.

Methods

Forty three patients suffering from painful plantar keratosis underwent a surgical excision of the lesion under local anesthetic. Following excision, the lesion was sent for histopathological analysis. The participants were seen for final review on average 19 months later. Recurrence of the lesions and histopathological diagnosis was recorded.

Results

In 20 (46.5%) of participants there was no recurrence of the skin lesion whilst in 23 (53.5%) the lesion recurred and was symptomatic. Initial histopathology indicated 22 cases of verruca pedis (51.2%), 19 cases of keratosis (44%), one (2.3%) epithelial cyst and one fibroepithelial polyp. Recurrence was noted in 64% of the verrucae and 79% of the keratosis group.

Conclusion

Full thickness excision of plantar skin lesions resolved the condition in fewer than half of the particpants in this study. Over half of lesions diagnosed clinically as plantar corns were in fact verrucae when analysed histopathologically. These findings indicate that bone surgery should only be considered once histopathological diagnosis of the lesions has been established. Full thickness lesion excision under local anesthetic may however be considered as a treatment option for sufferers of painful plantar corns as it is more effective than scalpel debridement and does not require specialised equipment. Podiatrists should consider full thickness excision under local anesthetic as the second line of treatment when routine debridement fails to relieve pain sufficiently. 

Felix M Lopez, FCPodS, Specialist Podiatric Registrar

Timothy E Kilmartin, FCPodS, PhD Consultant Podiatric Surgeon

PODIATRY NOW Vol 19, Number 10 | October 2016 

  • Comments (16)
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  • Quote:

    The controversy in plantar keratotic lesions was the difference between corn/tyloma versus porokeratosis. The genesis of the controversy was an attempt by podiatrists to find a histologic difference that would render a poro being considered as NOT ROUTINE. The answer as to whether they prevailed is UNKNOWN, and left to local carriers to determine. Several years ago a consultant to New York Blue Cross anointed the poro as "routine" and therefore a non covered diagnosis. However, an evaluation of such a lesion, provision of a diagnosis, and billed with an E/M has always been paid. Of course if done every month to disguise the fact that you are debriding the lesion you are in danger of a fraud allegation. I would bet that random phone calls to every carrier in the nation simply asking if debridement and padding of a porokeratosis is considered routine would result in a big, fat, zero difference in knowing the answer.

    What a mess!

    Also, in light of emerging evidence I defy any insurance carrier to provide a definitive diagnosis for a plantar foot lesion, from their office chairs and telephone, in the absence of histology.

  • Quote:

    I believe that the the histologic distinction between VP and corn or tyloma is quite clear. 

    I don't disagree that in a perfect specimen histopathological markers can provide for confidence in diagnosis. Not all samples present in this fashion and there can be histological overlap between the two lesions. Histological signs can be indicative but not always definitive of lesion characteristics. This is information provided by a dermatopathologist. I first read this information in an article or book (alas,many years ago, and I don't have the reference now) which first alerted me to this potential problem. 

  • I believe that the the histologic distinction between VP and corn or tyloma is quite clear. The controversy in plantar keratotic lesions was the difference between corn/tyloma versus porokeratosis. The genesis of the controversy was an attempt by podiatrists to find a histologic difference that would render a poro being considered as NOT ROUTINE. The answer as to whether they prevailed is UNKNOWN, and left to local carriers to determine. Several years ago a consultant to New York Blue Cross anointed the poro as "routine" and therefore a non covered diagnosis. However, an evaluation of such a lesion, provision of a diagnosis, and billed with an E/M has always been paid. Of course if done every month to disguise the fact that you are debriding the lesion you are in danger of a fraud allegation. I would bet that random phone calls to every carrier in the nation simply asking if debridement and padding of a porokeratosis is considered routine would result in a big, fat, zero difference in knowing the answer.

    I can tell you from experience that patients will pay 75, 100, 125 dollars for the comfort you can provide as often as they wish. Its only in the heads of the doctor that they wont.

  • Jeff, What case did I bring up?

  • Many years ago I looked at the histological diagnostic challenge to accurately differentiate between VP and corn (and the variations of tyloma seen clinically). At that time the dermatopathologist opined there can be overlap in histological presentation. I am curious to know if histological analysis has advanced over the years to provide a definitive diagnosis in all cases.

  • Dr. Markinson - I am always intrigued by legal cases. Are you able to comment on the case you brought up? Was the doc guilty of anything? Or not? What did the court decide?
  • Perfectly reasonable conclusion!

  • Quote:

    There is no problem, even under the rules, to include your suspicion of verruca, etc. as the diagnosis and do a biopsy. It is good and prudent medicine. However, unfortunately, too high a pecentage of clinicians can be counted on to abuse this. Again, done on firm clinical grounds in a patient in pain, who will seriously consider osteotomy, I see nothing wrong with this.

    So if you one adopts this protocol, and out of 100 patients who have a negative biopsy (positive for mechanical keratosis) only 2 go on to metatarsal surgery, you are an abuser as there was no real intent to correct with osseous surgery. This is what will happen in too many instances, in my humble opinion.

    That of course, does not and should not eliminate this protocol from use.

    Thank you for this clarification. Balanced against the abuse potential is the fact that a recurrence of the lesion is a significant factor. 64% of the VP recurred and 79% of the tyloma recurred following simple excision. This can leave room for a cure from a simple excision (job done) but that would not be the primary reason for this provision. 

    The patient will need to be counselled beforehand of the purpose of the biopsy i.e. to r/o and to confirm. When the diagnosis of a tyloma can be confirmed, and ruling out all other possible factors, the osteotomy (or associated surgical solution) can now be recommended with greater confidence (mindful of the fact that current literature indicates a 27% recurrence s/p osteotomy for tyloma).  

    This is a win:win for patient and doctor and can enhance and improve outcomes while providing  for the additional benefit of screening, of a suspicious lesion.


     

  • There is no problem, even under the rules, to include your suspicion of verruca, etc. as the diagnosis and do a biopsy. It is good and prudent medicine. However, unfortunately, too high a pecentage of clinicians can be counted on to abuse this. Again, done on firm clinical grounds in a patient in pain, who will seriously consider osteotomy, I see nothing wrong with this.

    So if you one adopts this protocol, and out of 100 patients who have a negative biopsy (positive for mechanical keratosis) only 2 go on to metatarsal surgery, you are an abuser as there was no real intent to correct with osseous surgery. This is what will happen in too many instances, in my humble opinion.

    That of course, does not and should not eliminate this protocol from use.

  • Dr. LaPorta ... ranks very highly on my list of all-time favorite scholars and educators. Dr. LaPorta's PRESENT lecture on MIS-bunion surgery was instrumental in the introduction, implementation and permanent addition, to the surgical toolbox, of this powerful tool. When Dr. LaPorta lectures I shut up and listen.

    A key point, in this discussion, is the billing structure. A Medicare covenant would decide what a doctor can or cannot bill. This is now a potentially flawed covenant, in the light of new evidence. A covenant that might now hamstring that doctor to make the correct and appropriate clinical decision based on sound suspicion, clinical examination, and backed up by EBM.

    If the figures are accurate and replicable, there is a greater than 50% probability that a recalcitrant plantar tyloma is misdiagnosed. What is a doctor to do, when required to work in a compensation framework that can offer no fee structure to provide a patient with a biopsy to determine with greater accuracy the nature of this pathology to determine a safe and effective treatment plan.

    Based on the EBM a doctor might well diagnose the VP, for example - there is a 50:50 probability the clinical diagnosis is correct, according to the available statistics. So, what happens , in the billing cycle, if his clinical diagnosis is wrong and the histopathology report returns a diagnosis of tyloma. Does that mean the doctor takes the hit and pays the bill? I am asking the billing experts among our readers to help clarify this conundrum.

    The doctor who advocates, correctly, for a biopsy before attempting a surgery that will alter a patient's anatomy will do so not only to provide relief from a painful foot condition, but will do so also to r/o a potentially deadly skin cancer or other tyloma-mimicking pathology. That such a lesion may well be uncommon is not contested - statistics are of little comfort to a patient, if this remains undiagnosed. In the worst case scenario this can be a fatal mistake.

    I guess ultimately this remains to be fought out in the judiciary system. Until then, the best a doctor can do is to advise a patient of the facts and let a patient decide for themselves if the risk of a misdiagnosis, or missed diagnosis, is worthy of dipping into their pocket to reach for that wallet.



      

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