Skin nonmelanocytic tumor

Adnexal tumors

Sweat gland derived (apocrine & eccrine glands)

Polymorphous sweat gland carcinoma


Resident / Fellow Advisory Board: Farres Obeidin, M.D.
Shira Ronen, M.D.
Saul Suster, M.D.

Minor changes: 25 October 2021

Copyright: 2019-2021, PathologyOutlines.com, Inc.

PubMed Search: Polymorphous sweat gland carcinoma


Shira Ronen, M.D.
Saul Suster, M.D.
Page views in 2021 to date: 620
Cite this page: Ronen S, Suster S. Polymorphous sweat gland carcinoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/skintumornonmelanocyticpolysweatglandcarcinoma.html. Accessed December 3rd, 2021.
Definition / general
Essential features
  • Histologically, the lesions are characterized by a cellular proliferation showing a combination of growth patterns, including trabecular, solid, tubular, cribriform or adenoid cystic and pseudopapillary (Am J Dermatopathol 2018;40:580)
  • Marked predilection for the distal extremities
Terminology
  • Polymorphous sweat gland carcinoma
  • Polymorphous low grade sweat gland carcinoma
  • PSGC
ICD coding
  • ICD-O-3 topography code: C44 - Skin
Epidemiology
Sites
Clinical features
Case reports
Treatment
  • Complete excision with conservative margins has been recommended as the preferred modality of treatment
Microscopic (histologic) description
  • Characterized by an admixture of multiple growth patterns within the same lesion, including trabecular, solid, tubular, cylindromatous and pseudopapillary, as well as prominent stromal changes, including hyalinization, hemorrhage, calcification and cystic changes
  • Tumors grow within the dermis in a generally well demarcated, pushing border but rarely can show infiltration at the edges
  • Parts of the tumor also show glandular differentiation and adnexal differentiation, such as abortive hair follicle formation and numerous squamous eddies
  • Tumors are predominantly composed of large epithelioid cells with atypical nuclei and abundant eosinophilic cytoplasm
    • Smaller cells with darker, angulated nuclei are scattered throughout the tumor
  • Spindling of tumor cells can be seen focally
  • Mitoses are present and can vary from case to case
Microscopic (histologic) images

Contributed by Shira Ronen, M.D.
Abortive hair follicle formation

Abortive hair follicle formation

Combination of growth patterns

Combination of growth patterns

Combination of growth patterns

Combination of growth patterns

Cribriform growth pattern

Cribriform growth pattern

Glandular differentiation

Glandular differentiation


Infiltration of surrounding fibroadipose tissue

Infiltration of surrounding fibroadipose tissue

Numerous squamous eddies

Numerous squamous eddies

Spindle cell appearance

Spindle cell appearance

Trabecular growth pattern Trabecular growth pattern

Trabecular growth pattern


Androgen receptor

Androgen receptor (AR)

CD56

CD56

Chromogranin

Chromogranin

CK5/6

CK5/6

p16

p16

p63

p63

Positive stains
Molecular / cytogenetics description
  • Negative for MYB-NFIB fusion
Sample pathology report
  • Neck mass, excision:
    • Polymorphous sweat gland carcinoma (see comment)
    • Comment: Sections show a relatively well demarcated tumor involving the dermis without a connection to the epidermis. The tumor shows multiple growth patterns including solid, trabecular, tubular and focal cribriform. Prominent hemorrhage, cystic changes and calcifications are seen. The cells are mostly epithelioid with prominent nucleoli and eosinophilic cytoplasm. Scattered mitotic figures are also observed. There is no evidence of significant cytologic atypia or necrosis. Overall, in the absence of a known or occult primary malignancy, the tumor is most consistent with a polymorphous sweat gland carcinoma. A clinical workup to exclude the possibility of metastasis, as clinically indicated, is recommended.
Differential diagnosis
  • Adenoid cystic carcinoma (ACC) (Am J Dermatopathol 1986;8:2):
    • ACC is characterized by monomorphic basaloid cells, which are arranged in tubules, elongated nests and cords
    • There are typically numerous cystic and ductular spaces with a prominent cribriform pattern
    • In comparison, polymorphous sweat gland carcinoma is characterized by striking variegation of histologic growth patterns, including glandular, trabecular, solid, cylindromatous and cribriform areas within the same tumor mass
    • MYB overexpression
    • Consistently expresses EMA
    • Positive for CD117, CEA, S100 and vimentin
  • Basal cell carcinoma (Am J Dermatopathol 1986;8:2):
    • Retains striking peripheral nuclear palisading and stromal retraction
  • Metastases from internal malignancies:
    • Can look histologically identical to polymorphous sweat gland carcinoma; therefore, clinical history and correlation with imaging are necessary
    • Negativity for p63 and CK5/6 favors a diagnosis of cutaneous metastasis of adenocarcinoma from internal organs over a primary cutaneous adnexal carcinoma
  • Benign and malignant adnexal neoplasm, such as ductal eccrine carcinoma, microcystic carcinoma and papillary digital eccrine carcinoma:
    • Key difference is the striking variegation of histologic growth patterns seen in polymorphous sweat gland carcinoma that would not be seen in other adnexal neoplasms
Board review style question #1
Which of the following statements is true about polymorphic sweat gland adenocarcinoma?

  1. It is characterized by an admixture of multiple growth patterns within the same lesion
  2. The most common location is the abdomen
  3. The tumor is common
  4. This tumor shows MYB-NFIB fusion
  5. It is a fast growing tumor
Board review style answer #1
A. It is characterized by an admixture of multiple growth patterns within the same lesion. The other answer choices are incorrect, since the tumor is shown to favor the extremities (choice B), the tumor is uncommon and only a few case reports and case series have been described (choice C), polymorphic sweat gland adenocarcinoma is negative for the MYB-NFIB fusion (choice D) and it is a slow growing, skin colored, firm dermal nodule (choice E).

Comment Here

Reference: Polymorphous sweat gland carcinoma
Board review style question #2
Which of the following immunohistochemical stains will show strong diffuse positivity in polymorphic sweat gland adenocarcinoma?

  1. CD117 and CEA
  2. p63 and p16
  3. Vimentin and cytokeratin AE1 / AE3
  4. Chromogranin and S100
  5. DOG1 and p40
Board review style answer #2
B. p63 and p16. The other answer choices are incorrect, since CD117 and CEA are negative (choice A), vimentin is negative within this entity, while cytokeratin AE1 / AE3 shows strong diffuse positivity (choice C), chromogranin stain shows focal expression, while S100 is negative within the tumor (choice D) and DOG1 is negative within this entity, while p40 shows strong diffuse positivity (choice E).

Comment Here

Reference: Polymorphous sweat gland carcinoma
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