Skip to main content
SpringerLink
Log in
Book cover

Pigmentary Skin Disorders pp 27–53Cite as

Dermatopathology Clues in Pigmentary Disorders

  • Chapter
  • First Online:

  • 1362 Accesses

Part of the book series: Updates in Clinical Dermatology ((UCD))

Abstract

Pigmentary disorders are a group of diseases characterized by a reduction, increase or alteration of pigment in the skin. On biopsy, hypopigmented lesions typically show a reduction of melanin in basal epidermal cells with an accompanying reduction in the number of melanocytes in some conditions. Hyperpigmented lesions show an increase in basal layer melanin with some melanophages in the upper dermis. However, these findings are shared by many different disorders and are not of much diagnostic value.

The focus in this chapter is on histopathological clues that can help make a diagnosis. These clues fall into three groups. There may be abnormalities related to components of the pigment system (melanocytes, melanin) as seen in dermal melanocytosis, vitiligo, carbon baby syndrome and hereditary melanosome transfer disorders. The second group includes pigmentary disorders with non-melanin pigment in the skin such as tattoos, pigmented purpuric dermatoses, talon noir, argyria, drug-induced pigmentation and ochronosis. The third and largest group consists of disorders with findings not related to the pigmentary system but distinctive enough to allow a diagnosis. These include lichen planus pigmentosus, connective tissue disorders, lichen sclerosus, Dowling-Degos disease, epidermodysplasia verruciformis, indeterminate leprosy and clear cell papulosis, among others.

Authors are employees of the Government of India

This is a preview of subscription content, log in via an institution.

Chapter
USD   29.95
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
eBook
USD   79.99
Price excludes VAT (USA)
  • Available as EPUB and PDF
  • Read on any device
  • Instant download
  • Own it forever
Softcover Book
USD   99.99
Price excludes VAT (USA)
  • Compact, lightweight edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info
Hardcover Book
USD   129.99
Price excludes VAT (USA)
  • Durable hardcover edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info

Tax calculation will be finalised at checkout

Purchases are for personal use only

Learn about institutional subscriptions

References

  1. Hirayama T, Suzuki T. A new classification of Ota’s naevus based on histopathological features. Dermatologica. 1991;183:169–72.

    Article  CAS  Google Scholar 

  2. Kang W, Lee E, Choi GS. Treatment of Ota’s nevus by Q-switched alexandrite laser: therapeutic outcome in relation to clinical and histopathological findings. Eur J Dermatol. 1999;9:639–43.

    CAS  PubMed  Google Scholar 

  3. Hori Y, Ouhara K, Miimura M, et al. Electron microscopy: ultrastructural observations of the extracellular sheath of dermal melanocytes in nevus of Ota. Am J Dermatopathol. 1982;4:245–51.

    Article  CAS  Google Scholar 

  4. Page DG, Swirsky JA, Kaugars GE. Nevus of Ota with associated palatal involvement. Oral Surg Oral Med Oral Pathol. 1985;59:282–4.

    Article  CAS  Google Scholar 

  5. Wilcox JC. Melanomatosis of skin and central nervous system. Am J Dis Child. 1939;57:391.

    Article  Google Scholar 

  6. Rathi SK. Bilateral nevus of ota with oral mucosal involvement. Indian J Dermatol Venereol Leprol. 2002;68:104.

    PubMed  Google Scholar 

  7. Sun CC, Lü YC, Lee EF, Nakagawa H. Naevus fusco-caeruleus zygomaticus. Br J Dermatol. 1987;1:545–53.

    Article  Google Scholar 

  8. Hori Y, Kawashima M, Oohara K, Kukita A. Acquired, bilateral naevus of Ota-like macules. J Am Acad Dermatol. 1984;10:961–4.

    Article  CAS  Google Scholar 

  9. Bhat RM, Pinto HP, Dandekeri S, Ambil SM. Acquired bilateral nevus of ota-like macules with mucosal involvement: a new variant of Hori’s nevus. Indian J Dermatol. 2014;59:293–6.

    Article  Google Scholar 

  10. Barnhill RL. Dermal melanocytoses, blue nevi, and related conditions. In: Barnhill RL, editor. Pathology of melanocytic nevi and melanoma. Boston: Butterworth-Heinemann; 1995. p. 131–52.

    Google Scholar 

  11. Kerl H, Massi D. Melanotic macules, simple lentigo and lentiginous melanocytic naevus. In: Leboit PE, editor. Pathology and genetics of skin tumours. Lyon: IARC; 2006. p. 103–4.

    Google Scholar 

  12. Wayte DM, Helwig EB. Halo nevi. Cancer. 1968;22:69–90.

    Article  CAS  Google Scholar 

  13. Menasche G, Ho CH, Sanal O, Feldmann J, Tezcan I, Ersoy F, et al. Griscelli syndrome restricted to hypopigmentation results from a melanophilin defect (GS3) or a MYO5A F-exon deletion (GS1). J Clin Invest. 2003;112:450–6.

    Article  CAS  Google Scholar 

  14. Menasche G, Feldmann J, Huodusse A, Desaymard C, Fischer A, Goud B, et al. Biochemical and functional characterization of Rab27a mutations occurring in Griscelli syndrome patients. Blood. 2003;101:2736–42.

    Article  CAS  Google Scholar 

  15. Pastural E, Barrat FJ, Dufoureq-Lagelouse R, Certain S, Sanal O, Jabade N, et al. Griscelli disease maps to chromosome 15q21 and is associated with mutations in the myosin Va gene. Nat Genet. 1997;16:289–92.

    Article  CAS  Google Scholar 

  16. Griscelli C, Durandy A, Guy Grand D, Daguillard F, Herzog C, Prunieras M. A syndrome associating partial albinism and immunodeficiency. Am J Med. 1978;65:691–702.

    Article  CAS  Google Scholar 

  17. Sanal O, Yel L, Kucukali T, Gilbert-Barnes E, Tardieu M, Texcan I, et al. An allelic variant of Griscelli disease: presentation with severe hypotonia, mental-motor retardation, and hypopigmentation consistent with Elejalde syndrome (neuroectodermal melanolysosomal disorder). J Neurol. 2000;247:570–2.

    Article  CAS  Google Scholar 

  18. LePoole IC, Van den Wijingaard RM, Westerhof W, Dutrieux RP, Das PK. Presence or absence of melanocytes in vitiligo lesions: an immunohistochemical investigation. J Invest Derma. 1993;100:816–22.

    Article  CAS  Google Scholar 

  19. Sharquie KE, Mehenna SH, Naji AA, Al-Azzawi H. Inflammatory changes in vitiligo: stage I and II depigmentation. Am J Dermatopathol. 2004;26:108–12.

    Article  Google Scholar 

  20. Attili VR, Attili SK. Lichenoid inflammation in vitiligo--a clinical and histopathologic review of 210 cases. Int J Dermatol. 2008;47:663–9.

    Article  Google Scholar 

  21. Wańkowicz-Kalińska A, van den Wijngaard RM, Tigges BJ, Westerhof W, Ogg GS, Cerundolo V, et al. Immunopolarization of CD4+ and CD8+ T cells to Type-1-like is associated with melanocyte loss in human vitiligo. Lab Investig. 2003;83:683–95.

    Article  Google Scholar 

  22. Yaghoobi R, Omidian M, Bagherani N. Vitiligo: a review of the published work. J Dermatol. 2011;38:419–31.

    Article  Google Scholar 

  23. Moellmann G, Klein-Angerer S, Scollay DA, Nordlund JJ, Lerner AB. Extracellular granular material and degeneration of keratinocytes in the normally pigmented epidermis of patients with vitiligo. J Invest Dermatol. 1982;79:321–30.

    Article  CAS  Google Scholar 

  24. Ruiz-Maldonado R, Tamayo L, Fernandez-Diaz J. Universal acquired melanosis: the carbon baby. Arch Dermatol. 1978;114:775–8.

    Article  CAS  Google Scholar 

  25. Abdallah MA, Abdallah MMA, Abdallah MA-R. Foreign body reactions. In: Bolognia JL, Jorizzo JL, Schaffer JV, editors. Dermatology. 3rd ed. England: Saunders Elsevier; 2012. p. 1573–83.

    Google Scholar 

  26. Ploysangam T, Breneman DL, Mutasim DF. Cutaneous pseudolymphomas. J Am Acad Dermatol. 1998;38:877–95.

    Article  CAS  Google Scholar 

  27. Slater DN, Durrant TE. Tattoos: light and transmission electron microscopy studies with x-ray microanalysis. Clin Exp Dermatol. 1984;9:1365–2230.

    Article  Google Scholar 

  28. Angeloni VL, Salasche SJ, Ortiz R. Nail, skin, and scleral pigmentation induced by minocycline. Cutis. 1987;40:229–33.

    CAS  PubMed  Google Scholar 

  29. Dereure O. Drug-induced skin pigmentation. Epidemiology, diagnosis and treatment. Am J Clin Dermatol. 2001;2:253–62.

    Article  CAS  Google Scholar 

  30. Job CK, Yoder L, Jacobson RR, Hastings RC. Skin pigmentation from clofazimine therapy in leprosy patients: a reappraisal. J Am Acad Dermatol. 1990;23:236–41.

    Article  CAS  Google Scholar 

  31. Trimble JW, Mendelson DS, Fetter BF, Ingram P, Gallagher JJ, Shelburne JD. Cutaneous pigmentation secondary to amiodarone therapy. Arch Dermatol. 1983;119:914–8.

    Article  CAS  Google Scholar 

  32. Argenyi ZB, Finelli L, Bergfeld WF, Tuthill RJ, McMahon JT, Ratz JL, et al. Minocycline-related cutaneous hyperpigmentation as demonstrated by light microscopy, electron microscopy and X-ray energy spectroscopy. J Cutan Pathol. 1987;14:176–80.

    Article  CAS  Google Scholar 

  33. Johansson EA, Kanerva L, Niemi KM, Lakomaa EL. Generalised argyria with low ceruloplasmin and copper levels in the serum. A case report with clinical and microscopic findings and a trial of penicillamine treatment. Clin Exp Dermatol. 1982;7:169–76.

    Article  CAS  Google Scholar 

  34. Pariser RJ. Generalized Argyria clinicopathologic features and histochemical studies. Arch Dermatol. 1978;114:373–7.

    Article  CAS  Google Scholar 

  35. Hori Y, Miyazawa S. Argyria: electron microscope and x-ray microanalysis. J Electron Microsc (Tokyo). 1977;26:193–201.

    CAS  Google Scholar 

  36. al-Talib RK, Wright DH, Theaker JM. Orange-red birefringence of gold particles in paraffin wax embedded sections: an aid to the diagnosis of chrysiasis. Histopathology. 1994;24:176–8.

    Article  CAS  Google Scholar 

  37. Zala L, Hunziker T, Braathen LR. Pigmentation following long-term bismuth therapy for pneumatosis cystoides intestinalis. Dermatology. 1993;187:288–9.

    Article  CAS  Google Scholar 

  38. Crissey JT, Peachy JC. Calcaneal petechiae. Arch Dermatol. 1961;83:501.

    Article  CAS  Google Scholar 

  39. Hafner J, Haenseler E, Ossent P, et al. Benzidine stain for the histochemical detection of hemoglobin in splinter hemorrhage (subungual hematoma) and black heel. Am J Dermatopathol. 1995;17:362–7.

    Article  CAS  Google Scholar 

  40. Cox NH, Piette WW. In: Burns DA, Breathnach SM, Cox NH, Griffiths C, editors. Textbook of dermatology, vol. 3. 8th ed. Oxford: Blackwell Scientific Publications; 1998. p. 2327–77.

    Google Scholar 

  41. Zawar VP, Mhaskar ST. Exogenous ochronosis following hydroquinone for melasma. J Cosmet Dermatol. 2004;3:234–6.

    Article  CAS  Google Scholar 

  42. Phillips JI, Isaacson C, Carman H. Ochronosis in black South Africans who used skin lighteners. Am J Dermatopathol. 1986;8:14–21.

    Article  CAS  Google Scholar 

  43. Albers SE, Brozena SJ, Glass LF, Fenske NA. Alkaptonuria and ochronosis: case report and review. J Am Acad Dermatol. 1992;27:609–14.

    Article  CAS  Google Scholar 

  44. Findlay GH, Morrison JGL, Simson IW. Exogenous ochronosis and pigmented colloid milium from hydroquinone bleaching creams. Br J Dermatol. 1975;93:613–22.

    Article  CAS  Google Scholar 

  45. Khunger N, Kandhari R. Dermoscopic criteria for differentiating exogenous ochronosis from melasma. Indian J Dermatol Venereol Leprol. 2013;79:819–21.

    Article  Google Scholar 

  46. Bhutani LK, Bedi TR, Pandhi RK, Nayak NC. Lichen planus pigmentosus. Dermatologica. 1974;149:43–50.

    Article  CAS  Google Scholar 

  47. Seo JK, Lee HJ, Lee D, Choi JH, Sung H-S. A case of linear lichen planus pigmentosus. Ann Dermatol. 2010;22:323–5.

    Article  Google Scholar 

  48. Kumar YH, Babu AR. Segmental lichen planus pigmentosus: an unusual presentation. Indian Dermatol Online J. 2014;5:157–9.

    Article  Google Scholar 

  49. Laskaris GC, Papavasiliou SS, Bovopoulou OD, Nicolis GD. Lichen planus pigmentosus of the oral mucosa: a rare clinical variety. Dermatologica. 1981;162:61–3.

    Article  CAS  Google Scholar 

  50. Vega ME, Waxtein L, Arenas R, Hojyo T, Dominguez-Soto L. Ashy dermatosis and lichen planus pigmentosus: a clinicopathologic study of 31 cases. Int J Dermatol. 1992;31:90–4.

    Article  CAS  Google Scholar 

  51. Kanwar AJ, Dogra S, Handa S, Parsad D, Radotra BD. A study of 124 Indian patients with lichen planus pigmentosus. Clin Exp Dermatol. 2003;28:481–5.

    Article  CAS  Google Scholar 

  52. Kim YC, Davis MD, Schanbacher CF, Su WP. Dowling-Degos disease (reticulate pigmented anomaly of the flexures): a clinical and histopathologic study of 6 cases. J Am Acad Dermatol. 1999;40:462–7.

    Article  CAS  Google Scholar 

  53. Singh S, Khandpur S, Verma P, Singh M. Follicular Dowling Degos disease: a rare variant of an evolving dermatosis. Indian J Dermatol Venereol Leprol. 2013;79:802–4.

    Article  Google Scholar 

  54. Kanwar AJ, Kaur S, Rajagopalan M. Reticulate acropigmentation of Kitamura. Int J Dermatol. 1990;29:217–9.

    Article  CAS  Google Scholar 

  55. Lestringant GG, Masouyé I, Frossard PM, Adeghate E, Galadari IH. Co-existence of leukoderma with features of Dowling-Degos disease: reticulate acropigmentation of Kitamura spectrum in five unrelated patients. Dermatology. 1997;195:337–43.

    Article  CAS  Google Scholar 

  56. Hanneken S, Rütten A, Pasternack SM, Eigelshoven S, El Shabrawi-Caelen L, Wenzel J, et al. Systematic mutation screening of KRT5 supports the hypothesis that Galli-Galli disease is a variant of Dowling-Degos disease. Br J Dermatol. 2010;163:197–200.

    CAS  PubMed  Google Scholar 

  57. Grosshans E, Geiger JM, Hanau D, Jelen G, Heid E. Early pigmentary changes in dowling-degos’ disease. J Cutan Pathology. 1984;7:77–87.

    Article  Google Scholar 

  58. Fajardo TT. Indeterminate leprosy: a 3 year study, clinical observations. Int J Lepr. 1971;39:94–5.

    Google Scholar 

  59. Vargas-Ocampo F. Pityriasis alba: a histologic study. Int J Dermatol. 1993;32:870–3.

    Article  CAS  Google Scholar 

  60. Copeman PWM, Wilson-Jones EWJ. Pigmented hairy epidermal nevus (Becker). Arch Dermatol. 1965;92:249–51.

    Article  Google Scholar 

  61. Khaitan BK, Manchanda Y, Mittal R, Singh MK. Multiple Becker’s naevi: a rare presentation. Acta Derm Venereol. 2001;81:374–5.

    Article  CAS  Google Scholar 

  62. Alhusayen R, Kanigsberg N, Jackson R. Becker nevus on the lower limb: case report and review of the literature. J Cutan Med Surg. 2008;12:31–4.

    PubMed  Google Scholar 

  63. Angelo C, Grosso MG, Stella P, et al. Becker’s nevus syndrome. Cutis. 2001;68:123–4.

    CAS  PubMed  Google Scholar 

  64. Matsuoka LY, Wortsman J, Goldman J. Acanthosis nigricans. Clin Dermatol. 1993;11:21–5.

    Article  CAS  Google Scholar 

  65. Joshi R. Idiopathic eruptive macular pigmentation with papillomatosis: report of nine cases. Indian J Dermatol Venereol Leprol. 2007;73:402–5.

    Article  Google Scholar 

  66. Weedon D, Haneke E, Martinka M, et al. Acanthomas. In: Leboit PE, editor. Pathology and genetics of skin tumours. Lyon: IARC; 2006. p. 39–47.

    Google Scholar 

  67. Kurban AK, Malak JA, Afifi AK, Mire J. Primary localized macular cutaneous amyloidosis: histochemistry and electron microscopy. Br J Dermatol. 1971;85:52–60.

    Article  CAS  Google Scholar 

  68. Brownstein MH, Hashimoto K, Greenwald G. Biphasic amyloidosis: link between macular and lichenoid forms. Br J Dermatol. 1973;88:25–9.

    Article  CAS  Google Scholar 

  69. Moriwaki S, Nishigori C, Horiguchi Y, Imamura S, Toda K, Takebe H. Amyloidosis cutis dyschromica: DNA repair reduction in the cellular response to UV light. Arch Dermatol. 1992;128:966–70.

    Article  CAS  Google Scholar 

  70. Ngo JT, Trotter MJ, Haber RM. Juvenile-onset hypopigmented mycosis fungoides mimicking vitiligo. J Cutan Med Surg. 2009;13:230–3.

    Article  Google Scholar 

  71. Das JK, Gangopadhyay AK. Mycosis fungoides with unusual vitiligo-like presentation. Indian J Dermatol Venereol Leprol. 2004;70:304–6.

    PubMed  Google Scholar 

  72. Werner B, Brown S, Ackerman AB. Hypopigmented mycosis fungoides is not always mycosis fungoides! Am J Dermatopathol. 2005;27:56–67.

    Article  Google Scholar 

  73. Attili VR, Attili SK. Vitiligoid lichen sclerosus: a reappraisal. Indian J Dermatol Venereol Leprol. 2008;74:118–21.

    Article  Google Scholar 

  74. Almeida HL Jr, Bicca Ede B, Breunig Jde A, Rocha NM, Silva RM. Scanning electron microscopy of lichen sclerosus. An Bras Dermatol. 2013;88:247–9.

    Article  Google Scholar 

  75. Elbendary A, Valdebran M, Parikh K, et al. Polarized microscopy in lesions with altered dermal collagen. Am J Dermatopathol. 2016;38:593–7.

    Article  Google Scholar 

  76. De Villiers WJ, Jordaan HF, Bates W. Systemic sclerosis sine scleroderma presenting with vitiligo-like depigmentation and interstitial pulmonary fibrosis. Clin Exp Dermatol. 1992;17:127–31.

    Article  Google Scholar 

  77. Smith ES, Hallman JR, DeLuca AM, Goldenberg G, Jorizzo JL, Sangueza OP. Dermatomyositis: a clinicopathological study of 40 patients. Am J Dermatopathol. 2009;31:61.

    Article  Google Scholar 

  78. Lutzner MA, Blanchet-Bardon C, Orth G. Clinical observations, virologic studies, and treatment trials in patients with epidermodysplasia verruciformis, a disease induced by specific human papillomaviruses. J Invest Dermatol. 1984;83:18s–25s.

    Article  CAS  Google Scholar 

  79. Yabe Y, Sadakane HJ. The virus of epidermodysplasia verruciformis: electron microscopic and fluorescent antibody studies. J Invest Dermatol. 1975;65:324–30.

    Article  CAS  Google Scholar 

  80. Elewski BE, Hughey LE, Sobera JO, Hay R. Fungal diseases. In: Bolognia JL, Jorizzo JL, Schaffer JV, editors. Dermatology. 3rd ed. England: Saunders Elsevier; 2012. p. 1251–84.

    Google Scholar 

  81. Landau M, Krafchik BR. The diagnostic value of café-au-lait macules. J Am Acad Dermatol. 1999;40:877–90.

    Article  CAS  Google Scholar 

  82. Pandhi RK, Bedi TR, Bhutani LK. Leucoderma in early syphilis. Br J Vener Dis. 1977;53:19–22.

    CAS  PubMed  PubMed Central  Google Scholar 

  83. Fiumara NJ, Cahn T. Leukoderma of secondary syphilis: two case reports. Sex Transm Dis. 1982;9:140–2.

    Article  CAS  Google Scholar 

  84. Miranda MF, Bittencourt Mde J, Lopes Ida C, Cumino Sdo S. Leucoderma syphiliticum: a rare expression of the secondary stage diagnosed by histopathology. An Bras Dermatol. 2010;85:512–5.

    Article  Google Scholar 

  85. Frithz A, Lagerholm B, Kaaman T. Leukoderma syphiliticum: ultrastructural observations on melanocyte function. Acta Derm Venereol. 1982;62:521–5.

    CAS  PubMed  Google Scholar 

  86. Kuo TT, Chan HL, Hsueh S. Clear cell papulosis of the skin. A new entity with histogenetic implications for cutaneous Paget’s disease. Am J Surg Pathol. 1987;11:827–34.

    Article  CAS  Google Scholar 

  87. Kumarasinghe SPW, Chin GY. Clear cell papulosis of the skin a case report from Singapore. Arch Pathol Lab Med. 2004;128:e149–52.

    PubMed  Google Scholar 

  88. Kim YC, Mehregan DA, Bang D. Clear cell papulosis: an immunohistochemical study to determine histogenesis. J Cutan Pathol. 2002;29:11–4.

    Article  Google Scholar 

  89. Gupta V, Bhatia R, Ramam M, Khanna N. Hypopigmented macules and papules following the lines of Blaschko: a novel variant of Darier’s disease. Int J Dermatol. 2016;55:e623–5.

    Article  Google Scholar 

  90. Rowley MJ, Nesbitt LT Jr, Carrington PR, Espinoza CG. Hypopigmented macules in acantholytic disorders. Int J Dermatol. 1995;34:390–2.

    Article  CAS  Google Scholar 

  91. Tharp MD. Mastocytosis. In: Bolognia JL, Jorizzo JL, Schaffer JV, editors. Dermatology. 3rd ed. England: Saunders Elsevier; 2012. p. 1993–2002.

    Google Scholar 

  92. Clayton R, Breathnach A, Martin B, Feiwel M. Hypopigmented sarcoidosis in the negro. Report of eight cases with ultrastructural observations. Br J Dermatol. 1977;96:119–25.

    Article  CAS  Google Scholar 

  93. Ackerman AB, De Viragh PA, Chonchitnant N. Neoplasms with follicular differentiation. Philadelphia: Lea&Febiger; 1995. p. 553.

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Department of Dermatology and Venereology, All India Institute of Medical Sciences, New Delhi, Delhi, India

    Riti Bhatia & M. Ramam

Authors
  1. Riti Bhatia
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. M. Ramam
    View author publications

    You can also search for this author in PubMed Google Scholar

Editor information

Editors and Affiliations

  1. Department of Dermatology, Fiona Stanley Hospital and University of Western Australia, Perth, Western Autralia, Australia

    Prasad Kumarasinghe

Rights and permissions

Reprints and permissions

Copyright information

© 2018 Government of India

About this chapter

Check for updates. Verify currency and authenticity via CrossMark

Cite this chapter

Bhatia, R., Ramam, M. (2018). Dermatopathology Clues in Pigmentary Disorders. In: Kumarasinghe, P. (eds) Pigmentary Skin Disorders. Updates in Clinical Dermatology. Springer, Cham. https://doi.org/10.1007/978-3-319-70419-7_2

Download citation

  • DOI: https://doi.org/10.1007/978-3-319-70419-7_2

  • Published:

  • Publisher Name: Springer, Cham

  • Print ISBN: 978-3-319-70418-0

  • Online ISBN: 978-3-319-70419-7

  • eBook Packages: MedicineMedicine (R0)

Publish with us

Policies and ethics

Search

Navigation