Arch. Derm. Forsch. 252, 17--22 (1975) © by Springer-Verlag 1975
Nerves and Nerve Endings in Pigmented Nevi Part II: U n c o m m o n Structural V a r i e t i e s L e n k e Szekeres Department of Dermatology, Medical University of Szeged (Director: ProL 1kT. Simon) (Hungary) l~eceived August 27, 1974
Summary. Unusual variations in the innervation of various pigmented ncvi (compound and intradermal) are reported. Zusammen/assung. UngewShnliche Variationen in der I n n e r v a t i o n verschiedener Formen pigmentierter Naevi werden beschrieben. Introduction The similarities b e t w e e n t h e c u t a n e o u s a n d nevic nerves h a v e been r e p o r t e d in a p r e v i o u s p a p e r (Szekeres, in press). I n this s t u d y u n u s u a l s t r u c t u r a l features of nevic n e u r a l elements will be demonstrated. The c o n s t r u c t i o n of p i g m e n t e d moles is v e r y difficult. Certain t y p e s can be considered as h a m a r t o m a s , consisting o f s m o o t h muscle cells, g l a n d u l a r , follicular a n d connective tissue e l e m e n t s in a d d i t i o n to n e v u s cells, nerves a n d b l o o d vessels. The s m o o t h muscle c o n t e n t o f some p i g m e n t e d nevi is v e r y a b u n d a n t . :Besides t r u e s m o o t h muscle elements, cells w i t h v e r y expressed p i n o c y t o t i e a c t i v i t y can also be f o u n d in t h e " n e u r o i d a r e a " of nevi. Dense p o p u l a t i o n of p i n o c y t o t i c vesicles has been o b s e r v e d b y Chouchkov (1971) in t h e inner a n d o u t e r core cells o f P a c i n i a n corpuscles a n d b y T c h e r e p n o v (1968) in the i n n e r core of t h e s a m e corpuscles. P i n o c y t o t i c vesicles as c o n s t a n t s t r u c t u r a l elements of t h e c a p s u l a t e d mechanor e c e p t o r has also been e s t a b l i s h e d b y P a t r i z i a n d Munger (1965) in t h e K r a u s e ' s b u l b e o f the r a t penis. I n t h e p e r i n u c l e a r c y t o p l a s m o f t h e s m o o t h muscle-like cells of nevi, free nerve endings can often be found. The c h a r a c t e r i s t i c s of these endings as well as other special v a r i a t i o n s or m i n o r s t r u c t u r a l differencies in the i n n e r v a t i o n o f nevi will also be r e p o r t e d .
Materials and Methods Specimens were obtained from twelve compound a n d ten intradermal nevi b y in toto
biopsies under local anaesthesia with Lidocain ®. Both types of nevi existed from the birth or the early childhood of the patients of both sex and with an average age of 30 years. The histological ~ype of nevi has been determined by light microscopic examinations. Materials were prefixed in 2.5°/o glutaraldehyde or Karnovsky solution (pH 7.4) for 2 hrs, and washed in cacodylate buffer for 2 hrs, postfixed in 1 °/00s04 solution buffered with Millonig or barbiturate-acetate buffer, pH 7.3 for I hr. After dehydration in increasing concentrations of ethanol solution and in two changes of propylene oxide, materials were embedded in Durcnpan M. Ultrathin sections were cut by a Reichert ultramicrotome and stained with uranyl acetate and lead citrate and viewed by a JEOL Jem 100 B electron microscope operated at 80 kV. 2 Arch. Derm. Forsch., Bd. 252
18
Lenke Szekcres
Fig. 1. Spindle-shaped cells with huge nucleus and scanty cytoplasm. _37 nucleus, n nucleolus, pv pinocytotic vesicles, M mitochondria, G Golgi complex, rp rounded profile, x 7000x2 Results In the deep, intradermal "neuroid area" of compound and dermal nevi, elongated, spindle-shaped cells with huge nucleus can often be found. Because of the undulated nuclear surface and the very expressed pinoeytotie activity along the cell borders, they are similar to the smooth muscle ceils. However, their exact nature can be determined with difficulty, because the cytoplasm is very scanty and the abundant intracytoplasmic microfilaments are irregularly arranged. Lucent, middle-sized mitoehondria, localized sometimes in the nuclear indentations, are also characteristic for these cells (Fig. 1). In the perinuclear cytoplasm of these cells, axons or axon-like structures can be observed. Their mesaxonal processes and the axolemma are clearly visible, the axoplasm contains vesicles and disintegrated mitochondria (Fig. 2). In other instances, near to the undulated nuclear surface, extremely lucent, rounded profiles can be seen surrounded by cytoplasmic microprojections and membrane complexes (Fig. 3). Rounded, empty profiles can be observed also in intercellular position. They are limited with a more or less preserved membrane (axolemma?). The axoplasm contain vesicles, membrane-enclosed amorphous or crystalline material. In the close vicinity of the axon-like structures, middle-dense, bizarre-shaped microprojections can be observed, which are filled with very finely granulated material. The microprojections with double-layered limiting membrane are in intimate contact with a periaxonale membrane. Between the axolemma and the periaxonale membrane, very fine granular material, similar to that of in microprojections, can be found (Fig.4).
Nerves and Nerve Endings in Pigmented Nevi. II
19
Fig. 2. An axon in the perinuclear cytoplasm of a spindle-shaped cell. N nucleus, ma mesaxon, al axolemma, v vesicles, M mitochondrion, B M basement membrane, pv pinocytotie vesicles, m/ microfilaments, t tubular structures, × 40000X 1.8 Single, axon-like elements with prominent axolemma and filamentous material in their axoplasm can also be seen in the different parts of the examined nevi. Stretched, large cells with extremely huge nucleus and very scanty cytoplasm surround these structures (Fig. 5). Discussion The findings described above can be interpreted with difficulty. Rounded and e m p t y profiles found in the perikaryon of smooth muscle-like cells can be compared with similar structures observed in the smooth muscle cells of guinea pig vas deferens (Merrillees et al., 1963). These profiles have been considered as intrusion of smooth muscle cells into each others, but their functional significance has not been discussed by the authors. The very dense network of the cytoplasmic mieroprojeetions and membrane complexes around the rounded or e m p t y profiles have not been reported until this time, as far as we know. The highly organized state (membrane complexes) of the cytoplasm around the axon-like intrusions m a y refer to a highly specialized metabolism between these structures and their surroundings. 2*
20
Lenke Szekeres
Fig.3. Rounded empty profile in the perikaryon of a smooth muscle-like cell. N nucleus, cytoplasmic microprojections, mc membrane complexes. × 20000×2
ep empty profile, al axolemma?, m p
The innervation of different smooth muscles has been investigated thoroughly by the electron microscope. Among others, Mark (1956) examined the uterine smooth muscle, Richardson (1962) and Merrillees et al. (1963) the smooth muscle of rat and guinea pig vas deferens, Oosaki and Ishii (] 964) described the fine structure of junction between smooth muscle cells in the rat small intestine. The ultrastructure of the skin smooth muscles and their innervation has been studied by Orfanos (1966). No similar observations about intracytoplasmic nerve endings and axon-like structures have been made. As regards the mieroprojeetions filled with finely granulated material and localized around axon-like elements, similar observations arc also lacking in the peripheral nervous system.
Fig.4. Intercellulare axon-like structures. N nucleus of a smooth-muscle-like cell, a axon?, al axolemm~?, v vesicle, m p mieroprojections, gr finely granulated material in the microprojections and between the axolemma and periaxoneal membrane, p m periaxoneal mem-
brane. × 15000×1.8 Fig.5. Axon-like element between stretched cells, a axon?, al axolemma?, N nucleus, c cytoplasm. 17000×2.5
Figs. 4 and 5
22
Lenke Szekeres
The significance of the s t r u c t u r a l v a r i a t i o n s described above can be h a r d l y established. T h e y m a y be either physiological varieties or pathological deviations, or the results of degenerative processes. The s t r u c t u r a l changes, a n d the complicated c o n s t r u c t i o n of n e u r a l elements m a y refer also to a v e r y intricate interrelat i o n s h i p between the different c o n s t i t u e n t s of nevi a n d their i n n e r v a t i o n . F u r t h e r i n v e s t i g a t i o n s a n d m a n y - s i d e d comparisons between the s t r u c t u r e of other n e u r a l elements a n d nevic nerves are needed for e s t i m a t i n g the real value a n d the possible consequence of the u n c o m m o n s t r u c t u r a l varieties.
Acknowledgement. The author would like to express her gratitude to Miss Elizabeth Szil£rd and Mr. Ivan Paskuj for their technical assistance. References 1. Chouchkov, H. N.: Ultrastructure of pacinian corpuscles in men and cats. Z. mikr.-anat Forsch. 88, 17--32 (1971) 2. Mark, J. S. T.: An electron microscope study of uterine smooth muscle. Anat. Rec. 125, 473--493 (1956) 3. Merrillees, N. C. R., Burnstock, G., Holman, M. E. : Correlation of fine structure and physiology of the innervation of smooth muscle in the guinea pig vas deferens. J. Cell Biol. 19, 529--550 (1963) 4. Oosaki, T., Ishii, S.: Junctional structure of smooth muscle cells. The ultrastructure of the regions of junction between smooth muscle ceils in the rat small intestine. J. Ultrastruct. Res. 10, 567--577 (1964) 5. Orfanos, C. : Elektronenmikroskopische Untersuchung glatter Hautmuskelfasern und ihrer Innervation. Dermatologica (Basel) 182, 445--459 (1966) 6. Patrizi, G., Manger, B. L. : The cytology of encapsulated nerve endings in the rat penis. J. UItrastruct. Res. 12, 500--515 (1965) 7. Richardson, K. C. : The fine structure of autonomic nerve endings in smooth muscle of the rat vas deferens. J. _Anat. (Lond.) 96, 427--442 (1962) 8. Szekeres, L. : Nerves and nerve endings in pigmented nevi, Part I. (In press) 9. Tcherepnov, V. L.: Ultrastructure of Pacinian corpuscles inner core. J. Evol. Biochem. Physiol. 4, 91--96 (1968) Dr. Lenke Szekeres Dept. of Dermatology Medical University of Szeged Pf: 480 H 6701 Szeged/Hungary
Nerves and Nerve Endings in Pigmented Nevi Part II: U n c o m m o n Structural V a r i e t i e s L e n k e Szekeres Department of Dermatology, Medical University of Szeged (Director: ProL 1kT. Simon) (Hungary) l~eceived August 27, 1974
Summary. Unusual variations in the innervation of various pigmented ncvi (compound and intradermal) are reported. Zusammen/assung. UngewShnliche Variationen in der I n n e r v a t i o n verschiedener Formen pigmentierter Naevi werden beschrieben. Introduction The similarities b e t w e e n t h e c u t a n e o u s a n d nevic nerves h a v e been r e p o r t e d in a p r e v i o u s p a p e r (Szekeres, in press). I n this s t u d y u n u s u a l s t r u c t u r a l features of nevic n e u r a l elements will be demonstrated. The c o n s t r u c t i o n of p i g m e n t e d moles is v e r y difficult. Certain t y p e s can be considered as h a m a r t o m a s , consisting o f s m o o t h muscle cells, g l a n d u l a r , follicular a n d connective tissue e l e m e n t s in a d d i t i o n to n e v u s cells, nerves a n d b l o o d vessels. The s m o o t h muscle c o n t e n t o f some p i g m e n t e d nevi is v e r y a b u n d a n t . :Besides t r u e s m o o t h muscle elements, cells w i t h v e r y expressed p i n o c y t o t i e a c t i v i t y can also be f o u n d in t h e " n e u r o i d a r e a " of nevi. Dense p o p u l a t i o n of p i n o c y t o t i c vesicles has been o b s e r v e d b y Chouchkov (1971) in t h e inner a n d o u t e r core cells o f P a c i n i a n corpuscles a n d b y T c h e r e p n o v (1968) in the i n n e r core of t h e s a m e corpuscles. P i n o c y t o t i c vesicles as c o n s t a n t s t r u c t u r a l elements of t h e c a p s u l a t e d mechanor e c e p t o r has also been e s t a b l i s h e d b y P a t r i z i a n d Munger (1965) in t h e K r a u s e ' s b u l b e o f the r a t penis. I n t h e p e r i n u c l e a r c y t o p l a s m o f t h e s m o o t h muscle-like cells of nevi, free nerve endings can often be found. The c h a r a c t e r i s t i c s of these endings as well as other special v a r i a t i o n s or m i n o r s t r u c t u r a l differencies in the i n n e r v a t i o n o f nevi will also be r e p o r t e d .
Materials and Methods Specimens were obtained from twelve compound a n d ten intradermal nevi b y in toto
biopsies under local anaesthesia with Lidocain ®. Both types of nevi existed from the birth or the early childhood of the patients of both sex and with an average age of 30 years. The histological ~ype of nevi has been determined by light microscopic examinations. Materials were prefixed in 2.5°/o glutaraldehyde or Karnovsky solution (pH 7.4) for 2 hrs, and washed in cacodylate buffer for 2 hrs, postfixed in 1 °/00s04 solution buffered with Millonig or barbiturate-acetate buffer, pH 7.3 for I hr. After dehydration in increasing concentrations of ethanol solution and in two changes of propylene oxide, materials were embedded in Durcnpan M. Ultrathin sections were cut by a Reichert ultramicrotome and stained with uranyl acetate and lead citrate and viewed by a JEOL Jem 100 B electron microscope operated at 80 kV. 2 Arch. Derm. Forsch., Bd. 252
18
Lenke Szekcres
Fig. 1. Spindle-shaped cells with huge nucleus and scanty cytoplasm. _37 nucleus, n nucleolus, pv pinocytotic vesicles, M mitochondria, G Golgi complex, rp rounded profile, x 7000x2 Results In the deep, intradermal "neuroid area" of compound and dermal nevi, elongated, spindle-shaped cells with huge nucleus can often be found. Because of the undulated nuclear surface and the very expressed pinoeytotie activity along the cell borders, they are similar to the smooth muscle ceils. However, their exact nature can be determined with difficulty, because the cytoplasm is very scanty and the abundant intracytoplasmic microfilaments are irregularly arranged. Lucent, middle-sized mitoehondria, localized sometimes in the nuclear indentations, are also characteristic for these cells (Fig. 1). In the perinuclear cytoplasm of these cells, axons or axon-like structures can be observed. Their mesaxonal processes and the axolemma are clearly visible, the axoplasm contains vesicles and disintegrated mitochondria (Fig. 2). In other instances, near to the undulated nuclear surface, extremely lucent, rounded profiles can be seen surrounded by cytoplasmic microprojections and membrane complexes (Fig. 3). Rounded, empty profiles can be observed also in intercellular position. They are limited with a more or less preserved membrane (axolemma?). The axoplasm contain vesicles, membrane-enclosed amorphous or crystalline material. In the close vicinity of the axon-like structures, middle-dense, bizarre-shaped microprojections can be observed, which are filled with very finely granulated material. The microprojections with double-layered limiting membrane are in intimate contact with a periaxonale membrane. Between the axolemma and the periaxonale membrane, very fine granular material, similar to that of in microprojections, can be found (Fig.4).
Nerves and Nerve Endings in Pigmented Nevi. II
19
Fig. 2. An axon in the perinuclear cytoplasm of a spindle-shaped cell. N nucleus, ma mesaxon, al axolemma, v vesicles, M mitochondrion, B M basement membrane, pv pinocytotie vesicles, m/ microfilaments, t tubular structures, × 40000X 1.8 Single, axon-like elements with prominent axolemma and filamentous material in their axoplasm can also be seen in the different parts of the examined nevi. Stretched, large cells with extremely huge nucleus and very scanty cytoplasm surround these structures (Fig. 5). Discussion The findings described above can be interpreted with difficulty. Rounded and e m p t y profiles found in the perikaryon of smooth muscle-like cells can be compared with similar structures observed in the smooth muscle cells of guinea pig vas deferens (Merrillees et al., 1963). These profiles have been considered as intrusion of smooth muscle cells into each others, but their functional significance has not been discussed by the authors. The very dense network of the cytoplasmic mieroprojeetions and membrane complexes around the rounded or e m p t y profiles have not been reported until this time, as far as we know. The highly organized state (membrane complexes) of the cytoplasm around the axon-like intrusions m a y refer to a highly specialized metabolism between these structures and their surroundings. 2*
20
Lenke Szekeres
Fig.3. Rounded empty profile in the perikaryon of a smooth muscle-like cell. N nucleus, cytoplasmic microprojections, mc membrane complexes. × 20000×2
ep empty profile, al axolemma?, m p
The innervation of different smooth muscles has been investigated thoroughly by the electron microscope. Among others, Mark (1956) examined the uterine smooth muscle, Richardson (1962) and Merrillees et al. (1963) the smooth muscle of rat and guinea pig vas deferens, Oosaki and Ishii (] 964) described the fine structure of junction between smooth muscle cells in the rat small intestine. The ultrastructure of the skin smooth muscles and their innervation has been studied by Orfanos (1966). No similar observations about intracytoplasmic nerve endings and axon-like structures have been made. As regards the mieroprojeetions filled with finely granulated material and localized around axon-like elements, similar observations arc also lacking in the peripheral nervous system.
Fig.4. Intercellulare axon-like structures. N nucleus of a smooth-muscle-like cell, a axon?, al axolemm~?, v vesicle, m p mieroprojections, gr finely granulated material in the microprojections and between the axolemma and periaxoneal membrane, p m periaxoneal mem-
brane. × 15000×1.8 Fig.5. Axon-like element between stretched cells, a axon?, al axolemma?, N nucleus, c cytoplasm. 17000×2.5
Figs. 4 and 5
22
Lenke Szekeres
The significance of the s t r u c t u r a l v a r i a t i o n s described above can be h a r d l y established. T h e y m a y be either physiological varieties or pathological deviations, or the results of degenerative processes. The s t r u c t u r a l changes, a n d the complicated c o n s t r u c t i o n of n e u r a l elements m a y refer also to a v e r y intricate interrelat i o n s h i p between the different c o n s t i t u e n t s of nevi a n d their i n n e r v a t i o n . F u r t h e r i n v e s t i g a t i o n s a n d m a n y - s i d e d comparisons between the s t r u c t u r e of other n e u r a l elements a n d nevic nerves are needed for e s t i m a t i n g the real value a n d the possible consequence of the u n c o m m o n s t r u c t u r a l varieties.
Acknowledgement. The author would like to express her gratitude to Miss Elizabeth Szil£rd and Mr. Ivan Paskuj for their technical assistance. References 1. Chouchkov, H. N.: Ultrastructure of pacinian corpuscles in men and cats. Z. mikr.-anat Forsch. 88, 17--32 (1971) 2. Mark, J. S. T.: An electron microscope study of uterine smooth muscle. Anat. Rec. 125, 473--493 (1956) 3. Merrillees, N. C. R., Burnstock, G., Holman, M. E. : Correlation of fine structure and physiology of the innervation of smooth muscle in the guinea pig vas deferens. J. Cell Biol. 19, 529--550 (1963) 4. Oosaki, T., Ishii, S.: Junctional structure of smooth muscle cells. The ultrastructure of the regions of junction between smooth muscle ceils in the rat small intestine. J. Ultrastruct. Res. 10, 567--577 (1964) 5. Orfanos, C. : Elektronenmikroskopische Untersuchung glatter Hautmuskelfasern und ihrer Innervation. Dermatologica (Basel) 182, 445--459 (1966) 6. Patrizi, G., Manger, B. L. : The cytology of encapsulated nerve endings in the rat penis. J. UItrastruct. Res. 12, 500--515 (1965) 7. Richardson, K. C. : The fine structure of autonomic nerve endings in smooth muscle of the rat vas deferens. J. _Anat. (Lond.) 96, 427--442 (1962) 8. Szekeres, L. : Nerves and nerve endings in pigmented nevi, Part I. (In press) 9. Tcherepnov, V. L.: Ultrastructure of Pacinian corpuscles inner core. J. Evol. Biochem. Physiol. 4, 91--96 (1968) Dr. Lenke Szekeres Dept. of Dermatology Medical University of Szeged Pf: 480 H 6701 Szeged/Hungary
