My journey into the world of onychology: A nail-biting adventure

A 54-year-old woman had a painful growth under her toenail, presenting as a bulbous lesion at the nail base, accompanied by onycholysis and nail plate destruction. Histopathology revealed an acanthotic epidermis with large glassy keratinocytes. The patient had a history of cutaneous manifestations characteristically evolving through three stages. What rare genodermatosis is suspected in this patient?

Characterised by the triad of growth plate arrest, proximal paronychia and xanthochromia, this distinctive clinical entity was first delineated in 2008 by de Berker et al. What is the name of this condition?

Samitz’s sign, characterised by a dystrophic, ragged or moth-eaten appearance of the cuticle, is a recognised manifestation of which disease?

Defined as the transitional zone between the nail bed and the hyponychium, this anatomical structure is often more readily visualised in the context of nail disorders such as pterygium inversum unguis. What is the name of this structure?

Considered the grandfather of European onychology, he is credited with the first descriptions of numerous nail conditions, including onychopapilloma, onychomatricoma, Bidet nail and nail degloving syndrome. Who is this legendary onychologist?

Onychopapilloma is a benign tumour of the distal matrix and nail bed characterised by localised distal subungual keratosis. A recent prospective cohort study has revealed an association between multiple onychopapillomas and a specific cancer genodermatosis. This syndrome carries an elevated risk of melanomas, basal cell carcinoma, and various internal malignancies. The presence of multiple onychopapillomas may serve as a novel cutaneous marker for which cancer syndrome?

Described by two leading figures in onychology, this syndrome encompasses three overlapping clinical presentations, typically characterised by thimble-shaped nail shedding. What is the name of this syndrome?

Yellow nail syndrome (YNS) classically presents with a triad of nail changes, lymphoedema and respiratory tract involvement. Which common metal is associated with YNS cases, often involving dental or orthopaedic implants?

A recently described matrical tumour of the nail bed presents with pachymelanonychia, a term reflecting its dual clinical features of nail thickening and pigmentation. The tumour can also manifest without pigmentation and exhibits three histopathologic variants: Acanthotic, papillomatous and keratogenous, with retarded maturation. What is the name of this tumour?

This diagnostic technique, originally involving the use of a 3-mm punch through a softened nail lesion followed by the application of a Hemoccult stick, has been recently modified to utilise hydrogen peroxide. What is the name of this technique, and what is its primary indication?

Subungual tumour in Incontinentia pigmenti. It is a late presentation of the disease which may be associated with bony destruction of the underlying phalanges.^[1]

Retronychia. It represents proximal ingrowth of the nail that occurs when the nail embeds backward into the proximal nail fold. The nail is thickened, yellow and with swelling most prominent at the interaction of the lateral horns and proximal nail fold. Nail plate avulsion with supplementary medical management is curative.^[2]

Dermatomyostitis.^[3]

Nail Isthmus.^[4]

Dr Robert Baran.^[5]

BReast CAncer gene 1-associated protein (BAP1) tumor predisposition syndrome.^[6]

Nail degloving syndrome was first described by Baran and Perrin.^[7] It presents anatomically in three overlapping ways: Thimble-shaped shedding with the nail plate and the surrounding skin, partial sloughing of the nail plate and adjacent tissue and shedding of the entire nail unit while sparing the distal digit epidermis. Lichen planus, toxic epidermal necrolysis and digital tip gangrene are common causes.

Titanium. YNS almost always involves upper and lower airways, giving rise to sinusitis and cough. It may be caused by the galvanic release of titanium ions by other metals, by the oxidative release of titanium ions by fluorides, or by the uptake of titanium dioxide from the digestive tract. The presence of titanium in the nails confirms the diagnosis, even in the absence of characteristic nail changes.^[8]

Onychocytic Matricoma. It is a recent and rarely described tumour arising from the nail matrix epithelium. Several subtypes have been proposed according to both histological features (acanthotic type, acanthotic and papillomatous type, keratogenous type with retarded maturation and germinotropic variant) and pigmentation (pigmented, melanocytic and non-pigmented).^[9]

Haneke’s technique. It is used to differentiate between subungual hematoma from subungual pigmentation. It involves driving a 3 mm punch through the softened nail without anaesthesia. Patient discomfort guides the depth of penetration. The punched-out section of the nail is then scrapped and analysed with a Hemoccult stick (or urinalysis reagent strip). If the strip changes colour, then this indicates haematoma.^[10]