Biomedical Engineering Reference
In-Depth Information
intact basement membrane prevents further transepidermal
loss. In biopsies obtained at 2-3 months and at 40 years, ink
particles are found only in dermal fibroblasts, predominantly
in a perivascular location beneath a layer of fibrosis, which had
replaced the granulation tissue (59).
Rabbit studies support that the fibroblast is responsible for
the stable intracutaneous life span of the tattoo (45). Ink par-
ticle aggregates were usually surrounded by a single membrane,
suggesting that they were partially free in the dermis; however,
they were not found to be free in several studies (40,41,45), and
in one study (42), they were present both extracellularly and
within fibroblasts. The interpretation of free extracellular tat-
too pigment may be a consequence of the difficulty in detect-
ing the single membrane seen by some investigators (40,41,45),
and in one study (42), tattoo particles are initially dispersed
diffusely as fine granules in the upper dermis as well as in verti-
cal foci at sites of injection but aggregate to a more focal con-
centrated appearance between 7 and 13 days (40,45). In another
study (42), black ink granules have a mean diameter of 4.42 ±
0.72 mm (40) compared with a mean particle diameter of
4.024 ± 0.76 mm when embedded in agar. Taylor and col-
leagues (41) found black pigment granules in tattoos to be
polymorphous, varying from 0.5 to 4.0 mm in diameter. Tur-
quoise and red pigment particles are larger than black granules.
In both amateur and professional tattoos, pigment ink depth
and density are highly variable, although greater variability of
size, shape, and location is noted with amateur tattoos. How-
ever, despite the diverse origins of tattoo pigment, the light and
electron microscopic appearances of all pigments are remark-
ably similar, except for their color.
Tattoo pigment granules are composed of three kinds of
loosely packed particles, ranging from 2 to 400 nm in diameter
(41): most often 40 nm; much less often 2-4 nm (slightly more
electron dense); and least frequently 400 nm (much more elec-
tron dense with a crystalline structure). A study of freshly
implanted eyeliner tattoo ink revealed particle size in the extra-
cellular matrix to be 0.1-1.0 nm, although the average particle
size in the pigment vial before implantation was 0.25 nm (60).
A prominent network of connective tissue surrounds each of
the fibroblasts containing ink particles, effectively entrapping
and immobilizing the cell. The life span of these fibroblasts is
unknown and may persist for the individual's life.
Although these studies give considerable detail regarding the
architectural morphology and physiology, they do not fully
explain the natural history of dermal tattoo ink. It is common
to observe that a tattoo becomes duller, bluer, more indistinct,
and blurred with time, presumably a consequence of ink par-
ticles moving deeper into the dermis by the action of mobile
phagocytic cells. Indeed, random biopsies of older tattoos
demonstrate pigment in the deep dermis as opposed to a more
superficial location of newer tattoos (61). Eventually tattoo ink
appears in regional lymph nodes of tattooed patients (48,62).
Box 4.1
Tattoo Ink Composition
Tattoo Ink/Pigment Color Ingredient
Black Iron oxide
Carbon
Logwood
Brown Ocher (ferric oxide)
Red Cinnabar⁄mercuric sulfi de
Cadmium red
Iron oxide⁄common rust
Naphthol-AS pigment
Yellow Cadmium yellow
Ochers
Curcuma yellow
Chrome yellow (PbCrO
4
, often
mixed with PbS)
Green Chromic oxide (Casalis green or
Anadomis green)
Lead chromate
Phthalocyanine dyes
Ferrocyanides and ferricyanides
Blue Azure blue
Cobalt blue
Copper phthalocyanine
Cobalt aluminate
Violet (purple) Manganese ammonium
pyrophosphate
Various aluminum salts
Dioxazine⁄carbazole
White Lead carbonate
Titanium dioxide
Barium sulfate
Zinc oxide
Henna Henna dye and paraphenylene-
diamine
Abbreviations
: PbCrO
4
, lead(II) chromate; PbS, lead sulfi de.
Source
: From
Ref. 52, by courtesy of Ravneet Ruby Kaur, William T. Kirby, and Howard
Maibach and the publishers.
histology
Only recently have we begun to understand the natural history
of an intradermally placed tattoo. A report of serial biopsy
examinations of tattoos placed at 24 hours; at 1, 2, and 3
months; and at 40 years previously has given some insight into
this process (53), as has an electron microscopic study of tat-
toos treated with the quality-switched (Q-switched) ruby
lasers (54), argon lasers, and tunable dye lasers (55). Initially,
ink particles are found within large phagosomes in the cyto-
plasm of both keratinocytes and phagocytic cells, including
fibroblasts, macrophages, and mast cells (56-58). The epider-
mis, epidermal-dermal junction, and papillary dermis appear
homogenized immediately after tattoo injection. At 1 month,
the basement membrane is reforming and aggregates of ink
particles are present within basal cells. In the dermis, ink-
containing phagocytic cells concentrate along the epidermal-
dermal border below a layer of granulation tissue closely
surrounded by collagen. Pigment is not seen within mast cells,
endothelial cells, pericytes, Schwann cells, in the lumina of
blood and lymphatic vessels, or extracellularly. At 1 month,
transepidermal elimination of ink particles through the epi-
dermis is still in progress, with ink particles present in kerati-
nocytes, macrophages, and fibroblasts. Reestablishment of an
side effects of tattoo placement
Tattoo pigment has been associated with occasional allergic
granulomas (63-67) and sarcoid reactions (46,68-70). Infections
(71) through cutaneous inoculation secondary to tattooing have
included tuberculosis (72), HIV (73), leprosy (74,75), hepatitis
(76-83), atypical mycobacteria (84), verucca (85-87), and zygo-
mycosis (88). Coincidental lesions, including sarcoidosis, B-cell
