Segmental neurofibromatosis: Immunocytochemicalanalysis of cutaneous lesionsSirldru Jaakkola, MB,a Ptiivi Muona, MB,a William D. James, MD,bMatti Hannuksela, MD, PhD,c Jaakko Karvonen, MD, PhD,c Juha Peltonen, MD, phD,a, *and Jouni Ditto, MD, PhDa Philadelphia, Pennsylvania, Washington, D. c.,and Oulu, Finland

Cutaneous lesions from three patients with segmental neurofibromatosis were evaluated.Routine histologic studies revealed the presence of rudimentary neural structures within anabundant collagenous matrix. The majority of the cells in all three cases expressed S-lOOprotein, suggesting their identity as Schwann cells. The stromal component stained positivelyfor fibronectin and type IV collagen; the latter indicated the presence of basement membranematerial. Embedded in the tumor mass were glandular epithelial structures that stained withepithelial membrane antigen antibody. Staining for factor VIII-,related antigen revealedvascular endothelium and multiple scattered mast cells. In one case strands of cells stainedwith antibodies to desmin, suggesting muscle cell differentiation. This case may represent adistinct subset of neurofibromas. (J AM ACAD DERMATOL 1990;22:617-21.)

The classic form of neurofibromatosis (NF-l)(also known as von Recklinghausen's disease) is anautosomal dominant hereditary disorder with a fre­quency ofapproximately 1 in 3000 to 4000 persons. I

The NF-l gene has been localized to the long armof chromosome 17,2,3 but the exact nature of thegenetic defect remains unknown. The diagnosis ofNF-l is based on the presence of cafe-au-Iait mac­ules, Lisch nodules (hamartomas of the iris), andneurofibromas.4-6

In segmental NF the cutaneous lesions are limitedto a dermatome or to a part of it.7Patients with thisvariant lack a family history of NF, and there is noevidence of generalized involvement. Some 20 cases

From the Departments of Dermatology, Biochemistry, and MolecularBiology, Jefferson Medical CoHege, and Section of Molecular Der­matology, Jefferson Institute of Molecular Medicine, Thomas Jef­ferson University, Philadelphia"; Walter Reed Army Medieal Cen­ter, Washington, D.e,b; and the Department of Dermatology, Uni­versity of Qulu,c

Supported in part by the U.S. Public Health Service,National InstitutesofHealth grants AR-28450, GM-28833, AR-35297, AR-38923, andT32AR-7561.

Accepted for publication May 31, 1989.Reprint requests: Jouni Uitto, MD, PhD, Department of Dermatology,

Jefferson Medical College, 1020 Locust St., M-46 Jefferson AlumniHaH, Philadelphia, PA 19107.

*Recipient of Young Investigator Award from National Neurofibro­matosis Foundation.

16/1/14389

Fig. 1. Case 1. Clinical presentation of patient withsegmental NF demonstrates cutaneous lesions in local­ized area on lateral aspect of right arm.

have been reported in the literature (for review,see references 8 and 9). We report three cases ofsegmental NF in which we studied cellular differen­tiation and matrix composition of the tumors.

617

618 Jaakkola el al.

Journal of theAmerican Academy of

Dermatology

Fig. 2. Lesions in segmental NF with antibodies to S-100 protein. A, Low-power viewdemonstrates positive reaction in majority of tumor cells; most intensive staining reaction isseen in cells associated with nerve structures (arrows). Bar:::: 100 p.m. B, Positive staining ofcells in small nerve traversing tumor. Bar = 25p.m. C, S-100 protein staining reveals both nu­clear (large arrow) and cytoplasmic (small arrows) patterns in Schwann cells. Asterisk de­notes solitary mast cell. Bar:::: 25 pm. (Peroxidase-antiperoxidase method with hematoxylin­eosin stain.)

CASE REPORTS

Case 1

A 69-year-old man who had multiple sessile tumors onan area of about lOX 10 em on the lateral aspect of theright arm (Fig. 1). The patient had been aware of the le­sions for more than 20 years. He had no family history ofNF. Examination revealed no pigmentary changes orother signs of NF.

Case 2

This case, involving a 31-year-old woman, and case 3have been reported previously.s Numerous soft tumorsdeveloped on the lateral aspect of the patient's left breast

at 14 years of age. She had no family history of NF. Nocafe-au-Iait spots, Lisch nodules, axillary freckling, orother neurofibromas were present.

Case 3

A 52-year-old man had had soft, I to 4 mm papuleson the volar aspect of the right wrist for 6 years. Hehad no family history of NF and no other evidence ofNF.8

MATERIAL AND METHODS

The tumors were excised with the use of a local anes­thetic, fixed with formalin, and embedded in paraffin.

Volume 22Number 4April 1990 Segmental neurofibromatosis 619

Fig. 3. Immunostaining for extracellular matrix components. A, Positive staining for typeIV collagen epitopes indicates abundance of basement membrane material in extracellularmatrix (arrows). Note positive staining reaction at dermoepidermal basement membranezone (arrowheads), whereas dermal connective tissue (asterisks) is devoid oftype IV collagenepitopes. B, Staining for fibronectin epitopes reveals continuous network in tumor stroma.Bar = 50 /Lm.

Routine histologic studies involved the use of hematoxy­lin-and-eosin stain. Immunostaining was performed bythe peroxidase-antiperoxidase method. 10

The following primary antibodies were used: poly­clonal rabbit antibodies to cow S-I00 protein, to humanplasma fibronectin, or to human factor VIII-related an-

tigen (Accurate Chemical & Scientific Corp., Westbury,N.Y.); rabbit antibodies to 7-S fragment of human typeIV collagen (gift from Dr. Leila Risteli, University ofOuIu, OuIu, Finland). Monoclonal antibodies to humanepithelial membrane antigen, human neurofilament pro­tein, and swine desmin were obtained from Dakopatts

620 Jaakkola et al.

4~....'~",Fig. 4. Case 1. Solitary muscle cells (m) scattered in le­sion shown in Fig. 1, Presence of adjacent Schwann cellsvisualized byimmunostaining for S-l00 protein (arrows).Bar = 25 ,urn. (Hematoxylin counterstain.)

(Glostrup, Denmark), Biomakor (Rehovot, Israel), andAccurate, respectively. Whole serum from nonimmu­nized mouse or rabbit (Cappel Laboratories, CooperBiomedical, Malvern, Pa.) was used in control reactions.

RESULTS

Four cutaneous tumors were excised from thethree patients. Routine histopathologic studies re­vealed the presence of neural structures within anabundant extracellular matrix, consistent with thediagnosis of neurofibroma.

The majority of tumor cells stained with anti­bodies to S-lOO protein; staining was most intensewithin the cells in the neural structures (Fig. 2, A andB). Examination of Schwann cells at higher magni­fication revealed that the S-l00 protein was presentin both the nucleus and cytoplasm in all cases (Fig.2, C).

With anti-type IV collagen antibody, diffusestaining within the tumors was noted (Fig. 3, A).Staining for fibronectin revealed a continuous net­work in the intercellular matrix (Fig. 3, B).

Additional immunocytochemical analyses

Journal of theAmerican Academy of

Dermatology

showed that embedded in the tumor mass wereglandular epithelial structureS that stained for epi­thelial membrane antigen. Vascular endotheliumand multiple scattered mast cells could be visualizedby staining for factor VIII-related antigen. Thesefindings are similar to our recent demonstration ofthe presence of various cytochemical epitopes in cu­taneous lesions of NF-1. l0

In one patient (case 1) solitary cells with the typ­ical morphology of muscle cells were present (Fig.4). These cells stained positively for desmin.

DISCUSSION

Our results indicate that the majority of cells insegmental NF are Schwann cells, as judged bystaining for S-100 protein. The distribution ofS-100 protein epitopes, however, was both nuclearand cytoplasmic, whereas the corresponding stain­ing pattern in cutaneous lesions of NF-I is predom­inantly nuclear. 10 Previously, cytoplasmic stainingfor S-100 protein has been observed in benignschwannomas.11 The latter lesions, however, consistof a single cell type, Schwann cells. These lesionshave a less abundant extracellular matrix and aredevoid of organized neural structures. 12 Although aprevious report!3 has suggested that the lesions insegmental NF resemble schwannomas ultrastruc­turally, the lesions in our study were clearly distinctfrom benign schwannomas.

The results of our study further indicated thepresence of matrix epitopes that correspond to typeIV collagen and fibronectin. These epitopes werealso noted in the lesions from patients with NF-1. 10

Previously, divergent cellular differentiation towardendothelial, epithelia, and muscle cell phenotype hasbeen detected only as part of organized structureswithin neurofibromas. 10 An unusual feature in case1was the presence ofdiffusely scattered solitary cellswith muscle cell differentiation. This finding sug­gests that these lesions may represent a distinctsubset of cutaneous neurofibromas with divergentdifferentiation. Alternatively these structures mayrepresent residual muscle cells present in the skin.Further analyses may be required to establishwhether the lesions of segmental NF are geneticallyrelated to those in patients with classic NF- L

REFERENCES

I. Crowe FW, Schull WJ, Neel lV. A clinical, pathological,and genetic study of multiple neurofibromatosis. Spring­field, Ill.: Charles C Thomas, 1956:153-4.

2. Seizinger SR, Rouleau GA, Ozelius LJ, et al. Genetic link-

Volume 22Number 4April 1990

age ofvon Recklinghausen's neurofibromatosis to the nervegrowth factor receptor gene. Cell 1987;49:589-94.

3. Barker D, Wright E, Nguyen K, et al. Gene for von Reck­linghausen's neurofibromatosis is in the pericentromericregion of chromosome 17. Science 1987;236:1100-2.

4. Riccardi VM. von Recklinghausen's neurofibromatosis. NEngl J Med 1981;305:1617-27.

5. Rubenstein AE. Neurofibromatosis: a review of the clinicalproblem. Ann NY Acad Sci 1986;486:1-13.

6. Rubinstein LJ. The ma1formativc central nervous systemlesions in the central and peripheral forms of neurofibro­matosis. Ann NY Acad Sci 1986;486:14-29.

7. Riccardi VM, Eichner JE. Neurofibromatosis: phenotype,natural history and pathogenesis. Baltimore: Johns Hop­kins University Press, 1986;178-80.

Segmental neurofibromatosis

8. Roth RR, Martinez R, James WD. Segmental neurofibro­matosis. Arch Dermatol 1987;123:917-20.

9. Rawlings CE, Wilkins RH, Cook WA, et aLSegmentalneurofibromatosis. Neurosurgery 1987;20:946-9.

10. Peltonen J, Jaakkola S, Lebwohl M, et al. Cellular differ­entiation and expression of matrix genes in type 1 neurofi­bromatosis. Lab Invest 1988;59:760-71.

11. Nakajima T, Watanabe S, Sato Y, et aI. An immunoper­oxidase study of S-100 protein distribution in norma! andneoplastic tissues. Am J Surg Patho] 1982;6:715-27.

12. Harkin Jc. Pathology of nerve sheath tumors. Ann N YAcad Sci 1986;486:147-54.

13. Oranje AP, Vuzevski VD, Kalis T J, et al. Segmental neu­rofibromatosis. Br J DermatolI985;112:107-12.

Facial skin complaints and work at visualdisplay units

An epidemiologic study of office employees

M. Berg, MD,a S. Liden, MD,a and O. Axelson, MDb Stockholm and Linkoping, Sweden

A questionnaire about skin rashes and their symptoms was sent to 3877 randomly selectedoffice employees with different degrees of exposure to video display units (participation rate96.6%). From this group 809 randomly selected persons were examined and interviewed.Itching and burning sensations with few visible signs were more common among persons whowere highly exposed than among thosein the nonexposed category. Objectivefacial signs werenot significantly more common among persons in the highly exposed category. No dose­response effect was observed regarding the amount of video display unit exposure and objec­tive skin signs. Unilateral skin rashes and skin malignancies were found in the same frequencyin both highly exposed and the nonexposed persons. This study does not provide support forthe hypothesis that video display unit work induces any recognized type of facial skin disease.(J AM ACAD DERMATOL 1990;22:621-5.)

Skin problems among visual display unit (VDU)workers have been reported from Norway,1 theUnited Kingdom,2 the United States,3 andSweden.4-6 Most patients had rosacea or rosacea­like dermatitis. 1,2, 4-6 Since the fall of 1985 theSwedish mass media and the salaried employees'

From the Department of Dermatology, Karolinska Hospital, Stock­holm,' and the Department of Occupational Medicine, UniversityHospital, Linkoping.b

Supported by the Swedish Work Environment Fund, Stockholm.

Accepted for publication June I, 1989.

Reprint requests: M. Berg, MD, Department of Dermatology, KaroJin­ska Hospital, S-104 01 Stockholm, Sweden.

16/1/1439]

press have debated the health effects of VDU expo­sure and skin problems from VDU work have beenclaimed to be relatively common. A few epidemi­ologic studies of these problems have beenpublished.7-JO Various physical factors have beensuggested as the cause of VDU-related skin prob­lems (e.g., electrostatic and magnetic fields of theVDU, electrostatic charge of the operator, deposi­tion of airborne particles, x-ray emissions, andultraviolet radiation), but documentation isscant. II -13 A provocation study found no relationbetween the symptoms of the patients and electro­static or magnetic fields from the VDU.13 Ultravi­olet and ionizing radiation are negligible. 14

A large-scale epidemiologic study of randomly

621