MISCELLANEOUS SURGICAL PATHOLOGY

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CHAPTER 19 MISCELLANEOUS SURGICAL PATHOLOGY

Pathology of pediatric hair samples
Blood film examination for vacuolated lymphocytes

PATHOLOGY OF PEDIATRIC HAIR SAMPLES

Introduction (Smith et al 2005)

• Hair shafts may be examined using routine light microscopy
• Wide range of morphological abnormalities (Figs 19.1, 19.2)

image many associated with specific underlying disorders
• Several important clinical groups of pediatric patients where light microscopic examination of hair may provide valuable diagnostic information

image erythrodermic infant with immunodeficiency

– trichorrhexis invaginata with Netherton’s syndrome

image neurologically impaired child

– pili torti with Menkes disease
– tiger tail anomaly with trichothiodystrophy

image immunological/hematological disorders and ectodermal dysplasias may also exhibit abnormal hair appearances

• Around half of samples for these indications will show some abnormality
image

Fig. 19.1

image

Figs 19.1–19.2 Photomicrographs of hair shafts showing patterns of normal variation.

Types of sample and handling

(Garn 1951, Leblond 1951, Eilers 1982, Shelley 1983, Caserio 1987, Crounse 1987, De Berker 1997, Smith et al 2005)

• Shaft abnormalities are best seen in cut samples

image plucking may cause unwanted breakages, especially with trichorrhexis, making the sample non-diagnostic

• Follicle disorders (such as loose anagen syndrome) can only be diagnosed on a sample of plucked hair containing the root

image misshapen anagen hairs

– lack external root sheaths
– bulbs distorted
– cuticle just above the root has a ‘wrinkled stocking’ appearance

· above this zone the rest of the hair shaft appears normal

• Plucking carried out either by:

image gripping less than 10 hairs between finger and thumb, or
image gripping a couple of rows of hairs with a needle holder at the base

– and pulling sharply

• Cut hairs should be cut close to the scalp to allow examination of the shaft
• Hairs are usually dry mounted without medium

image placed into a rectangular frame with double sided sticky tape edges on a microscope slide
image hairs lined up in parallel

– securing ends to the frame

image coverglass placed over the frame

• In cases examined for pigment abnormalities (Chediak–Higashi or Griscelli)

image use a mountant (DPX)

• Examine as many strands as possible

image not every hair may demonstrate morphological abnormalities in the lengths examined

Histopathological features

Normal hair

• Normal hair shafts are cylindrical

image smooth surface
image varying diameters
image ovoid or round profiles in cross section

• Normal hair pigment within the shaft is uniformly distributed

Types of morphological abnormality

• Wide range of morphological abnormalities may be seen including:

image non-specific changes:

– weathering

· lifting and damage of cuticular cells

– splits

· especially distal shaft

– twisting (but not classical pili torti)
– mild flattening or grooving

image pili torti (Fig 19.3)

– twists completely rotated through 180° around their long axis at irregular intervals
image trichorrhexis nodosa (Figs 19.4, 19.5)

– swellings along the shafts associated with areas of breakage
– indicates that the hair is easily breakable as a result of injury
image trichorrhexis invaginata (Fig 19.6) (Ito et al 1984)

– nodular swellings with one part apparently indenting the ‘cupped’ other portion

· resembles a bamboo shoot

image pili canaliculati et trianguli

– longitudinal canalicular depressions with kidney shaped or triangular cross sections

image pigment clumping or hypopigmentation
image ‘tiger tail’ appearance under polarized light (Fig 19.7)
image root abnormalities

image

Fig 19.3 Photomicrograph of hair shaft showing pili torti with flattening and twists completely rotated through 180° around the long axis at irregular intervals.

image

Fig. 19.4

image

Figs 19.4–19.5 Photomicrographs of hair shafts showing trichorrhexis nodosa, with areas of shaft breakage.

image

Fig 19.6 Photomicrograph of hair shaft showing trichorrhexis invaginata, with nodular swellings and ‘cup’ appearance, in Netherton syndrome.

image

Fig 19.7 Photomicrograph of hair shaft showing banding under polarized light; tiger-tail anomaly.

Associations with specific diagnoses

• Around 25% of cases submitted have abnormalities compatible with specific diagnoses
• Menkes disease (Williams et al 1978, Martin et al 1978)

image pili torti (Fig 19.8)

– Xq12-q13 ATP7

· encodes ATPase Cu2+ transporting molecule

• Netherton’s syndrome

image trichorrhexis invaginata

– autosomal recessive
– mutations in SPINK5 gene (Descargues et al 2005)

· encodes serine protease inhibitor
· wide range of mutations

• Trichothiodystrophy (Hansen et al 1993, Liang et al 2005)

image ’tiger tail’ anomaly

– 19q13.2-q13.3 ERCC2/XPD

· encode helicase subunits of transcription/repair vector TFIIH

• Griscelli syndrome

image 15q21 MYO5A/RAB27A (Pastural et al 2000, Menasche et al 2003, Celik et al 2007)
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