Prostate gland & seminal vesicles

Squamous carcinomas

Adenosquamous carcinoma


Editorial Board Member: Bonnie Choy, M.D.
Deputy Editor-in-Chief: Maria Tretiakova, M.D., Ph.D.
Kenneth A. Iczkowski, M.D.

Last author update: 20 February 2024
Last staff update: 20 February 2024

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PubMed Search: Adenosquamous carcinoma prostate

Kenneth A. Iczkowski, M.D.
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Cite this page: Iczkowski KA. Adenosquamous carcinoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/prostateadenosquamouscarcinoma.html. Accessed March 28th, 2024.
Definition / general
  • Adenosquamous carcinoma of the prostate is characterized by presence of both glandular / acinar and squamous components
Essential features
  • Adenosquamous prostatic carcinoma is a very rare aggressive tumor
  • Critical to exclude other sources of the squamous component through clinical history, examinations, endoscopy and immunostains
  • 67% of cases are associated with prior androgen deprivation therapy or radiotherapy
  • Diagnosis requires proper morphology and immunostaining with prostate specific markers (prostate specific antigen [PSA], prostate specific membrane antigen [PSMA], prostatic specific acid phosphatase [PSAP] and prostatic acid phosphatase [PAP]), which should be positive in the glandular and negative in the squamous component
ICD coding
  • ICD-O: C61.9 - prostate, NOS
  • ICD-10: C61 - malignant neoplasm of the prostate
Epidemiology
Sites
  • Prostate, often with extraprostatic extension and seminal vesicle involvement
Pathophysiology
  • Theories
    • Metaplastic transformation of adenocarcinoma frequently after treatment; this is supported by a case of adenosquamous carcinoma in which the squamous component rose from 5% before adjuvant radiotherapy to predominantly squamous after radiotherapy (Eur J Cancer 2018;95:109)
    • Collision tumor: intermingling of squamous and glandular components with no abrupt transition argues against this, as does the observation that squamous component may be PSAP reactive (Hum Pathol 1984;15:87, Int J Urol 2005;12:319, Scientific World Journal 2006;6:2491)
    • Arises from pluripotent stem cells capable of multidirectional differentiation (Urol Case Rep 2019;29:101084)
Etiology
  • Often association with status postandrogen ablation or prostatic radiotherapy
Clinical features
Diagnosis
  • Histologic findings are established on transurethral resection (consistent with frequent obstructive uropathy) or biopsy
  • Imaging cannot distinguish it from generic prostate cancer
Laboratory
Radiology description
Radiology images

Images hosted on other servers:
Tumor abutting anorectal canal

Tumor abutting anorectal canal

Prognostic factors
  • 30% 5 year survival (Rare Tumors 2010;2:e47)
  • For patients undergoing prostatectomy it is 63%, whereas for those not undergoing prostatectomy 1 year survival is 39%
Case reports
Treatment
Microscopic (histologic) description
  • In addition to the usual glandular prostate cancer component, there is a component of cells with eosinophilic cytoplasm
  • Keratin pearls and intercellular bridges are required to diagnose squamous cell carcinoma
  • Additional sarcomatoid transformation has been rarely reported (Histopathology 2020;77:890, Scientific World Journal 2006;6:2491)
Microscopic (histologic) images

Contributed by Susan Prendeville, M.D. and Gladell Paner, M.D.
Biopsy, prominent squamous areas

Biopsy, prominent squamous areas

Same, with obvious keratin

With obvious keratin

Mixed components, postradiation setting

Mixed components, postradiation setting

Transition, squamous to glandular

Transition, squamous to glandular

Negative stains
Molecular / cytogenetics description
Sample pathology report
  • Prostate, left apex, biopsies:
    • Prostatic adenosquamous carcinoma, Gleason 4 + 4 (score = 8) (see comment)
    • Comment: 30% of the tumor is a squamous component with cells showing intracellular and extracellular keratin and intercellular bridges. This finding correlates with the documented antiandrogen dosing the patient underwent after diagnosis of a Gleason 3+3 carcinoma 4 years ago. Adenosquamous carcinoma is an aggressive tumor.
Differential diagnosis
  • Secondary involvement by squamous neoplasms arising in bladder, urethra or anorectal region:
    • Clinical endoscopic findings negative in these sites
    • Normal serum PSA
    • Limited use for immunostains
  • Pure squamous carcinoma:
    • Absence of a contiguous or separate focus of glandular cancer in the specimen
  • Admixed prostate cancer with urothelial neoplasms arising in bladder or urethra:
    • Keratin pearls and intercellular bridges are required to diagnose squamous cell carcinoma
    • If these findings are absent and if GATA3 or uroplakin II staining are present, the lesion is urothelial and not prostatic
  • Basal cell hyperplasia with squamous features (Hum Pathol 2005;36:531):
    • Lack of atypia of squamous cells
    • Absent invasive glandular component
    • Cytologic features of basal cells including nuclear vacuoles
Board review style question #1

Which of the following findings would exclude a definite diagnosis of prostatic adenosquamous carcinoma in a biopsy?

  1. Close intermingling of squamous and glandular tumor components
  2. Lack of a history of hormone deprivation or radiotherapy for prostate cancer
  3. Prior history of muscle invasive urothelial carcinoma with squamous features
  4. PSA staining usually negative in the squamous component
  5. Staining of the squamous tumor with cytokeratin 34 beta E12
Board review style answer #1
C. Prior history of muscle invasive urothelial carcinoma with squamous features. Prior history of a squamous cancer in the vicinity of the prostate is critical. A urothelial carcinoma, including that with squamous features, can easily invade the prostate. Answer D is incorrect because indeed the squamous component does lose reactivity for PSA in most adenosquamous tumors. Answer E is incorrect because the squamous component of adenosquamous carcinoma should stain with cytokeratin 34 beta E12. Answer B is incorrect because while many cases of adenosquamous carcinoma do have an association with hormonal or radiotherapy, quite a few reported cases do not. Answer A is incorrect because indeed there often is close intermingling of squamous and glandular components of the tumor.

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Reference: Adenosquamous carcinoma
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