Collision lesions

From dermoscopedia

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 Editor: Andreas Blum

 Author(s): Andreas Blum     ·  Rainer Hofmann     ·  Florentia Dimitriou
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Author(s) Andreas Blum · Rainer Hofmann · Florentia Dimitriou
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Status released
Status update July 5, 2018
Status by Ralph P. Braun


Collision tumors/lesions of the skinThis glossary term has not yet been described., detectable with dermoscopyThe examination of [skin lesions] with a 'dermatoscope'. This traditionally consists of a magnifier (typically x10), a non-polarised light source, a transparent plate and a liquid medium between the instrument and the skin, and allows inspection of skin lesions unobstructed by skin surface reflections. Modern dermatoscopes dispense with the use of liquid medium and instead use polarised light to cancel out skin surface reflections., can occur in all possible combinations of the different cells of the epidermal and/or dermal cell layers (Table 1, Figure 1) (1).

  • Combinations of epidermal-epidermal collision tumors are more often found in UV-exposed skin areas in older patients than epidermal-dermal combinations.
  • To diagnose correctly any possible collision tumor/lesion, the dermoscopic analysis of colorsThis glossary term has not yet been described. and differential structuresThis glossary term has not yet been described. must be perfomed in all four "quadrants" (2,3).
  • The switch between polarized and non-polarized lightThis glossary term has not yet been described. might also be helpful (4,5).

    Skin lesions or tumors with their original cell types of the different skin layers (focused only on skin lesions detectable by dermoscopy) (1).
    Layer of the SkinThis glossary term has not yet been described. Cell Type or Functional Structure Associated Proliferations / Neoplasms
    Epidermis Keratinocytes Solar lentigoThis glossary term has not yet been described.

    Seborrheic keratosisThis glossary term has not yet been described.
    Actinic keratosisActinic keratosis (also called solar keratosis and senile keratosis; abbreviated as AK) is a pre-cancerous patch of thick, scaly, or crusty skin.
    Bowenalso known as squamous cell carcinoma in situ[1] is a neoplastic skin disease. It can be considered as an early stage or intraepidermal form of squamous cell carcinoma. It was named after John T. Bowen's disease
    KeratoacanthomaThis glossary term has not yet been described.
    Squamous cell carcinomaThis glossary term has not yet been described.

    Basal cell layer (non-differentiated folliculo-sebaceous-apocrine germ) Trichoblastoma

    Basal cell carcinomais the most common skin cancer, and one of the most common cancers in the United States.[1] While BCC has a very low metastatic risk, this tumor can cause significant disfigurement by invading surrounding tissues

    Melanocytes MelanocyticThis glossary term has not yet been described. nevusThis glossary term has not yet been described.

    MelanomaThis glossary term has not yet been described.

    Merkel cells Merkel cell carcinoma
    Dermis Blood capillaries AngiomaAngiomas are benign tumors derived from cells of the vascular or lymphatic vessel walls (endothelium) or derived from cells of the tissues surrounding these vessels.[1][2] Angiomas are a frequent occurrence as patients age, but they might be an indicator of systemic problems such as liver disease. They are not commonly associated with malignancy.
    Melanocytes Melanocytic (dermal or blue) nevus


    Fibroblasts DermatofibromaDermatofibromas are hard solitary slow-growing papules (rounded bumps) that may appear in a variety of colours, usually brownish to tan; they are often elevated or pedunculated. A dermatofibroma is associated with the dimple sign; by applying lateral pressure, there is a central depression of the dermatofibroma.

    Dermatofibrosarcoma protuberans

    Non-Langerhans cells/histiocystes Xanthogranuloma
    Infundibulo-follicular-sebaceous unit Sebaceous hyperplasiaThis glossary term has not yet been described.

    Milia cyst
    Adnexal (benignis any condition that is harmless in the long run or malignantThis glossary term has not yet been described.) tumor

    Myocytes Kaposi sarcomaThis glossary term has not yet been described.

    ReferencesThis is material contained in a footnote or bibliography holding further information.: [1][2][3][4][5][6][7]
    1. An Atlas of Dermoscopy, Second Edition. Marghoob A. et al. CRC Press; 2012.
    2. Blum A, Siggs G, Marghoob AA, et al. (2017) Collision skin lesions-results of a multicenter study of the International Dermoscopy Society (IDS). Dermatol Pract Concept 2017;7(4):12;51-62
    3. Braga JC, Scope A, Klaz I, Mecca P, Spencer P, Marghoob AA. Melanoma mimicking seborrheic keratosis: an error of perception precluding correct dermoscopic diagnosis. J Am Acad Dermatol 2008:58:875-880
    4. Kittler H, Marghoob AA, Argenziano G, et al. Standardization of terminology in dermoscopy/dermatoscopy: Results of the third consensus conference of the International Society of Dermoscopy. J Am Acad Dermatol. 2016;74:1093-1106
    5. Wang SQ, Dusza SW, Scope A, Braun RP, Kopf AW, Marghoob AA. Differences in dermoscopic images from nonpolarized dermo¬scope and polarized dermoscope influence the diagnostic accuracy and confidence level: a pilot study. Dermatol Surg 2008;34:1389-1395
    6. Pan Y, Gareau DS, Scope A, Rajadhyaksha M, Mullani NA, Mar¬ghoob AA. Polarized and nonpolarized dermoscopy: the explana¬tion for the observed differences. Arch Dermatol 2008;144:828-829.
    7. Blum A, Maltagliati-Holzner P, Deinlein T, Hofmann-Wellenhof R. Collision tumors in dermoscopy : A new challenge. Hautarzt 2018 May 4. doi: 10.1007/s00105-018-4172-z.