Dermatologic neoplasms

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This article deals with dermatologic neoplasms. It includes dermatologic cancer, which can be deadly. Collectively, dermatologic cancers are the most common form of cancer.

Squamous cell carcinoma

Main article: Squamous carcinoma

General

Precursor:[1]

  • Actinic keratosis (solar keratosis).
    • Clinical: yellow-brown scaly, patches, sandpaper sensation.

Risk factors:[1]

  • Sun exposure.
  • Immune suppression (e.g. organ transplant recepients).

Notes:

  • Keratocathoma - see non-malignant skin disease.
    • Some don't believe this entity exists.
      • These people sign this entity as low grade squamous cell carcinoma, keratoacanthoma type.[2]

Microscopic

Basal cell carcinoma

General

  • Very common.
  • Sun exposed skin.
  • Very rarely metastasizes - so rare... some don't think this is really a malignancy.

Clinical

  • Telangiectasias.
  • Raised pearly nodule.

As part of a syndrome

Microscopic

Features:[4]

  • Nest of hyperchromatic (i.e. blue) cells (similar in appearance to basal cells) with:
    • Palisading of cells at the edge of the cell nests.
    • Artefactual separation of cells (forming the nests) from the underlying stroma.

Notes:

DDx:

Melanoma

Main article: Malignant melanoma

General

  • Known as the great mimicker in pathology; it may look like many things.

Microscopic

Features:

  • Classic appearance of melanoma:
    • Loosely cohesive; mix of small nests of cells, single cells.
    • Mixed of spindle and ovoid cell morphology.
    • +/-Occasional large binucleated cells.
    • Cytoplasm: brown pigment (melanin).
    • Prominent (large) red nucleoli (like in serous carcinoma of the ovary).
    • Marked nuclear pleomorphism - variation in cell size, shape & staining (like in serous carcinoma of the ovary).
    • Nuclear pseudoinclusions (like in papillary thyroid carcinoma).

Dermatofibrosarcoma protuberans

  • Abbreviated DFSP.

General

  • Dermal location.
  • Destroys adnexal structures.

Treatment:[5]

  • Wide excision.
  • May include imatinib (Gleevec).

Microscopic

Features:[5]

  • Dermal spindle cell lesion with storiform pattern.
    • Spokes of the wheel-pattern.
  • Contains adipose tissue within the tumour -- key feature.
    • Described as "honeycomb pattern" and "Swiss cheese pattern".

Notes:

  • Adnexal structure within tumour are preserved -- this is unusual for a malignant tumour.

DDx:

  • Dermatofibroma - has entrapment of collagen bundles at the edge of the lesion.

IHC

Panel:[6]

  • CD34 +ve.
    • Usually negative in dermatofibroma.[7][8]
  • Factor XIIIa -ve.
    • Usually positive in dermatofibroma.[7][8]
  • S100 -ve (screen for melanoma).
  • Caldesmin -ve (screen for muscle differentiation).
  • Beta-catenin. (???)
  • MIB-1 (proliferation marker).
    • Should not be confused with MIB1 a gene that regulates apoptosis.

Molecular

A characteristic translocation is seen:[9] t(17;22)(q22;q15)

Cutaneous B-cell lymphoma

  • Abbreviated CBCL.

General

  • CBCL is less common than cutaneous T-cell lymphoma (CTCL).[10]

Microscopic

Features:

  • Dermal lymphoid infiltrate.
  • "Grenz zone" - space between the epidermis and the dermal infiltrate - key feature.

IHC

  • B cell and T cell markers.

Cutaneous T-cell lymphoma

  • Abbreviated CTCL.

General

  • Mycosis fungoides - is a subtype (???).
  • CTCL is more common than cutaneous B-cell lymphoma (CBCL).[11][12]

Microscopic

  • Atypical lymphocytes:
    • Have folded "cerebriform" nuclei; Sezary-Lutzner cells.[13]
  • Grouping:
    • Nests in the epidermis - known as "Pautrier microabscesses".
    • Single lymphocytes in epidermis; "lymphocyte exocytosis".[14]
    • Short linear arrays of lymphocytes along the basal layer of the epidermis; "epidermotropism".[13]

Images:

IHC

Features:

Merkel cell carcinoma

General

Features:[16]

  • Rare.
  • Aggressive course/poor prognosis.
  • Neuroendocrine-like.[17]

Etiology:

  • Polyomavirus (?).[16]
  • Immunocompromised/immunosuppressed (e.g. organ transplant recipients).

Microscopic

Features:[18]

  • Nests or sheets or trabeculae.
  • Scant cytoplasm.
  • Nuclear moulding.
  • Multiple small nucleoli.
  • Usually mitotically active.

Image:

IHC

  • CK7 -ve, CK20 +ve

Eccrine carcinoma

General

  • Arises from the proximal sweat duct.

Microscopic

Features:

  • Pleomorphic nuclei with nucleoli.
  • Duct-like structures - key feature.
  • Extends from dermis into epidermis (follows path of a benign sweat duct).

Image: Eccrine carcinoma - intermed. mag. (WC).

Eccrine poroma

General

  • Benign tumour arising from the distal sweat duct.
  • Erythematous - gross.

Microscopic

Features:[19]

  • Broad sheets of basaloid cells containing ductal structures - key feature.
  • Biphasic stroma:
    1. Edematous stroma.
    2. Sclerotic stroma.
  • Moderate nuclear pleomorphism.
  • +/-Occasional mitoses.

Notes:

  • Area above gland appears crusted.

Kaposi sarcoma

See Kaposi sarcoma.

See also

References

  1. ↑ 1.0 1.1 Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson; Aster, Jon (2009). Robbins and Cotran pathologic basis of disease (8th ed.). Elsevier Saunders. pp. 1180. ISBN 978-1416031215.
  2. ↑ RS. 17 May 2010.
  3. ↑ URL: http://emedicine.medscape.com/article/1101146-diagnosis. Accessed on: 6 May 2010.
  4. ↑ 4.0 4.1 Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson; Aster, Jon (2009). Robbins and Cotran pathologic basis of disease (8th ed.). Elsevier Saunders. pp. 1180-1. ISBN 978-1416031215.
  5. ↑ 5.0 5.1 Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson; Aster, Jon (2009). Robbins and Cotran pathologic basis of disease (8th ed.). Elsevier Saunders. pp. 1183. ISBN 978-1416031215.
  6. ↑ AP. May 2009.
  7. ↑ 7.0 7.1 Abenoza P, Lillemoe T (October 1993). "CD34 and factor XIIIa in the differential diagnosis of dermatofibroma and dermatofibrosarcoma protuberans". Am J Dermatopathol 15 (5): 429–34. PMID 7694515.
  8. ↑ 8.0 8.1 Goldblum JR, Tuthill RJ (April 1997). "CD34 and factor-XIIIa immunoreactivity in dermatofibrosarcoma protuberans and dermatofibroma". Am J Dermatopathol 19 (2): 147–53. PMID 9129699.
  9. ↑ Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson; Aster, Jon (2009). Robbins and Cotran pathologic basis of disease (8th ed.). Elsevier Saunders. pp. 1249. ISBN 978-1416031215.
  10. ↑ URL: http://emedicine.medscape.com/article/1099540-overview. Accessed on: 24 August 2010.
  11. ↑ URL: http://emedicine.medscape.com/article/1099540-overview. Accessed on: 24 August 2010.
  12. ↑ URL: http://emedicine.medscape.com/article/1098342-overview. Accessed on: 24 August 2010.
  13. ↑ 13.0 13.1 Klatt, Edward C. (2006). Robbins and Cotran Atlas of Pathology (1st ed.). Saunders. pp. 385. ISBN 978-1416002741.
  14. ↑ URL: http://www.mdconsult.com/das/book/body/199872830-2/0/1709/I4-u1.0-B978-0-443-06694-8..50117-2--f2.fig. Accessed on: 6 May 2010.
  15. ↑ Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson; Aster, Jon (2009). Robbins and Cotran pathologic basis of disease (8th ed.). Elsevier Saunders. pp. 1185. ISBN 978-1416031215.
  16. ↑ 16.0 16.1 Calder, KB.; Smoller, BR. (May 2010). "New insights into merkel cell carcinoma.". Adv Anat Pathol 17 (3): 155-61. doi:10.1097/PAP.0b013e3181d97836. PMID 20418670.
  17. ↑ Pulitzer, MP.; Amin, BD.; Busam, KJ. (May 2009). "Merkel cell carcinoma: review.". Adv Anat Pathol 16 (3): 135-44. doi:10.1097/PAP.0b013e3181a12f5a. PMID 19395876.
  18. ↑ Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 491. ISBN 978-0781765275.
  19. ↑ URL: http://www.pathconsultddx.com/pathCon/diagnosis?pii=S1559-8675(06)70190-5. Accessed on: 2 July 2010.
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