pilomatrixoma and genetic testing

Pilomatrixoma and Genetic Testing

Anyone studying pilomatrixomas will discover they can be associated with a variety of conditions. 

  • Turner syndrome
  • Gardner syndrome
  • Myotonic dystrophy

are the most common three mentioned, but there are a whole host of others reported (usually as isolated case reports) – Rubinstein-Taybi, Sotos, Stickler, Kabuki syndromes; Trisomies 19 and 9; xeroderma pigmentosum; basal cell naevus Syndrome; sarcoidosis.

The question arises – who to consider referring for genetic testing? Many papers casually mention ‘multiple’ pilomatrixomas being associated with syndromes, but don’t say how often they’re associated or just how many constitutes ‘multiple’ . About 3.5% of cases of pilomatrixoma will have more than one. On one hand you don’t want to miss the chance to diagnose an associated condition earlier than it would have otherwise become apparent. On the other hand you don’t want to unnecessarily worry large numbers of families by referring every child with more than one pilomatrixoma. Most people wouldn’t consider referring a child with a single pilomatrixoma for genetic testing. Some balance is required.

pilomatrixoma and genetic testing

There is a recent paper tackling this question. 1 Thee authors suggest referral for genetic screening in the following circumstances

  • 6 or more pilomatrixomas
  • 1 in the setting of a family history of myotonic dystrophy, 1st-degree relative with colon cancer or FAP-related syndrome, or family history of pilomatrixomas
  • 1 in the setting of a clinical features suggestive of Turner or Rubenstein-Taybi syndromes.

Including a recommendation for screening if a 1st-degree relative had colon cancer doesn’t narrow it down very much. And why did they decide on 6 or more? If you gather the extant literature on cases with multiple pilomatrixomas, and include those with associated conditions (as these authors did), you can work out the sensitivity and specificity, &c of using various numbers. These are their data, based on 6 or more pilomatrixomas using that cutoff to look for myotonic dystrophy, FAP-related diseases, Turner, and Rubenstein-Taybi syndromes:

Sensitivity (%) (95% CI) 46.30 (32.62-60.39)
Specificity (%) (95% CI) 95.52 (90.51-98.34)
Positive Predictive Value (%) (95% CI) 80.65 (64.43-90.55)
Negative Predictive Value (%) (95% CI) 81.53 (77.46-85.01)

So, using 6 as your cutoff will have a false positive rate of just under 5% – that’s good if you want to avoid distressing families. But the sensitivity is under 50%, so you’ll detect less than half of all cases. Each time you refer someone, or not, there’s an 80% chance you’ve done the right thing for that patient.

What happens if you refer everyone with 2 or more pilomatrixomas?

There are 214 cases in the literature with 2 or more, 54 of them (~25%) had an underlying genetic condition. Here are the numbers:

Association with multiple PM 2-5 (%) 6-9 (%) 10 (%) Total
Myotonic dystrophy 20 (58.8) 4 (11.8) 10 (29.4) 34
FAP-related syndromes 2 (33.3) 1 (16.7) 3 (50.0) 6
Turner syndrome 3 (33.3) 4 (44.4) 2 (22.2) 9
Rubenstein-Taybi syndrome 4 (80) 0 (0.0) 1 (20.0) 5
Total syndromic 29 (53.7) 9 (16.7) 16 (29.6) 54
Total familial 21 (80.8) 5 (19.2) 0 (0.0) 26
Total sporadic 128 (95.5) 3 (2.2) 3 (2.2) 134
Total 178 (83.2) 17 (7.9) 19 (8.9) 214

So you can essentially decide for yourself where your cutoff should lie, and how many you’re prepared to miss in order not to distress, or vice versa.

Personally, I’m comfortable with “six, or suspicious”. In other words, all patients with six or more, or if I think something’s up with smaller numbers. To do that I’ve had to re-read the features of all of the associated conditions, in particular how they look in the early phases.

 

1 Ciriacks K, Knabel D, Waite MB. Syndromes associated with multiple pilomatricomas: When should clinicians be concerned? Pediatric Dermatology 2020; 37: 9–17.

burns first aid

Burns First Aid

Burns first aid is the principal difference between a burn that heals well with dressings and one that may result in a permanent scar.

You leave the coffee to percolate near the edge of the bench. There’s a smash, followed by a scream, and it brings you running back to the kitchen to find your toddler covered in hot coffee. What do you do now??

 

In Virchester, we hear this story every week. It’s among the most common histories of the new burns we seen annually. Hot liquid scalds are the single most common mechanism. Hot beverage scalds occur when the child pulls the liquid down on themselves, or when a (usually) parent with a cuppa trips over a child. What the parents did next often makes the difference between a burn that heals just with dressings, versus one that may leave a permanent physical scar. There is no substitute for effective burns first aid.

The most effective first aid is to remove clothing, and run the affected area under cool running water for 20 minutes. 1

burns first aid

Some is better than none, and late is better than never. 2 Anything else you read online is inaccurate, inadequate, or inconsistent. 3 Anything else you might do is less effective as first aid. 4 Ice is bad, don’t use it. 1 Some traditional first aid substitutes (aloe vera, honey, toothpaste) coat the burn and reduce pain by occluding exposed nerve endings from air currents. They do little to decrease the metabolic burden the burnt tissue is under. Running water appears to be more effective than still water, perhaps because it washes away pro-inflammatory cytokines from the area. Research to explain this is ongoing. For smaller children be conscious to guard against heat loss. Queensland is pretty hot most of the year, and our tap water is between 2 and 15 degrees year-round. This temperature range is equally effective, so the water doesn’t have to be really cold. Tepid water, rather than cold, will mitigate hypothermia in children. Wrapping the child in a warm towel after 20 minutes cold running water will also help prevent heat loss.

Cover the wound with plastic film (cling film, Saran wrap, Glad wrap). It’s essentially sterile out of the box, so you don’t have to worry about infection. 5 Burns clinicians can see through it to assess the burn without having to undress the wound and cause further distress and pain to your child.

Provide your child with pain relief, and work to decrease their (and your) anxiety. Proper analgesia is not just kind, it’s also associated with faster wound healing. 6 Anxiety can mimic pain and appears to have many of the same outcomes with respect to delays in healing.

Seek expert medical attention, ideally directed by a Burns Centre.

The majority of children’s burns are scald injuries, and are superficial partial thickness. With effective burns first aid and modern dressings, the majority will heal without scarring. Modern dressings are more expensive than traditional dressings and so may not be stocked by your local family practitioner. Many of these burns are likely to heal even with old-fashioned dressings, but do you REALLY want to take that chance with your child. It makes no sense to me to go to all that trouble of providing effective first aid, only to then put a second- or third-tier dressing on the burn. We use silver-containing, antimicrobial dressings on all children’s burns in our Burns Centre. There are no exceptions to this rule.

References

1 Cuttle L, Kempf M, Kravchuk O, et al. The optimal temperature of first aid treatment for partial thickness burn injuries. Wound Repair Regen 2008; 16: 626–34.

2 Cuttle L, Kempf M, Liu P-Y, Kravchuk O, Kimble RM. The optimal duration and delay of first aid treatment for deep partial thickness burn injuries. Burns 2010; 36: 673–9.

3 Burgess JD, Cameron CM, Cuttle L, Tyack Z, Kimble RM. Inaccurate, inadequate and inconsistent: A content analysis of burn first aid information online. Burns 2016; 42: 1671–7.

4 Cuttle L, Pearn J, McMillan JR, Kimble RM. A review of first aid treatments for burn injuries. Burns 2009; 35: 768–75.

5 Liao AY, Andresen D, Martin HCO, Harvey JG, Holland AJA. The infection risk of plastic wrap as an acute burns dressing. Burns 2014; 40: 443–5.

6 Miller K, Rodger S, Kipping B, Kimble RM. A novel technology approach to pain management in children with burns: A prospective randomized controlled trial. Burns 2011; 37: 395–405.

Declaration

Craig McBride is a paediatric burns surgeon. He works in the Burns Centre responsible for many of the cited publications above. He’s not an author on any of them. He has no commercial ties to any company selling water packaged as a first aid treatment for burns.