Adrenal gland & paraganglia

Other tumors

Adenomatoid tumor


Editorial Board Member: Bonnie Choy, M.D.
Deputy Editor-in-Chief: Maria Tretiakova, M.D., Ph.D.
Katherine A. Lehman, B.S.
Debra L. Zynger, M.D.

Topic Completed: 16 September 2021

Minor changes: 16 September 2021

Copyright: 2002-2021, PathologyOutlines.com, Inc.

PubMed Search: Adrenal adenomatoid tumor

Katherine A. Lehman, B.S.
Debra L. Zynger, M.D.
Page views in 2020: 719
Page views in 2021 to date: 1,007
Cite this page: Lehman KA, Zynger DL. Adenomatoid tumor. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/adrenaladenomatoid.html. Accessed November 29th, 2021.
Definition / general
  • Rare benign nonfunctioning tumor of the adrenal gland of mesothelial origin
Essential features
  • Proliferation of gland-like or vascular-like spaces lined by attenuated to columnar mesothelial cells
  • Rare nonfunctioning tumor of the adrenal gland typically found incidentally
  • Often confused on imaging and microscopy with tumors such as lymphangioma
  • Accurate diagnosis relies upon microscopic examination, typically with immunohistochemistry
  • Benign, with no reported cases of tumor recurrence following surgical excision
Epidemiology
Sites
  • Adrenal cortex and medulla
Pathophysiology
  • Thought to arise via entrapment of primitive mesenchymal cells from the Müllerian tract within the adrenal gland versus embolized mesothelial cells (Am J Surg Pathol 2003;27:969)
Etiology
  • Unknown
Clinical features
  • Typically asymptomatic and discovered incidentally
  • Rarely, reports of symptoms resulting from elevations in adrenal hormones (homovanillic acid, hyperaldosteronism) secondary to stimulation of normal adrenal parenchyma by tumor (Adv Anat Pathol 2009;16:424)
Diagnosis
  • Diagnosis cannot be made using imaging alone, as adrenal adenomatoid tumors lack specific radiologic features
  • Surgical excision (preferred) or core biopsy with subsequent histopathologic evaluation necessary for diagnosis
  • Easily confused with more common tumors when evaluated via light microscopy so immunohistochemistry plays a key role in accurate diagnosis (Adv Anat Pathol 2009;16:424)
Radiology description
  • Nonspecific; misdiagnosed as nonfunctioning adrenocortical tumor or other more common entities
  • May be well visualized on CT or MRI, with a wide range of presentations reported on imaging
  • Appearance ranges from homogeneous and solid to cystic degeneration or calcifications (Eur Radiol 1999;9:552)
Radiology images

Contributed by Firas G. Petros, M.D.
CT of left adrenal mass CT of left adrenal mass CT of left adrenal mass CT of left adrenal mass

CT of left adrenal mass


MRI of left adrenal mass MRI of left adrenal mass MRI of left adrenal mass MRI of left adrenal mass

MRI of left adrenal mass

Prognostic factors
  • Favorable prognosis, with no reported cases of recurrence following excision
Case reports
Treatment
  • Complete surgical resection
Gross description
Gross images

Contributed by Debra L. Zynger, M.D.
Ill defined spongy lesion

Ill defined spongy lesion



Images hosted on other servers:

White solid and cystic surface

Cut surface of cystic lymphangioma-like adrenal adenomatoid tumor

Cystic surface

Cystic spongy surface

Solid gray surface

Microscopic (histologic) description
  • Well circumscribed to infiltrative into surrounding cortex and medulla
  • Can infiltrate into periadrenal adipose
  • Growth patterns include microcysts, tubules, macrocysts / cavernous and pseudovascular with papillary and anastomosing structures lined by endothelial-like cells (Adv Anat Pathol 2009;16:424)
  • Cells are flattened to hobnailed and bland with no appreciable mitoses
  • Lymphoid aggregates and interspersed lymphocytes are frequently present
  • Dystrophic calcifications are frequent
  • Areas with abundant fine calcifications can have an empty, vacuolated appearance
  • Surrounding fibrosis may be seen
Microscopic (histologic) images

Contributed by Debra L. Zynger, M.D.
Cystic lesion

Cystic lesion

Anastomosing channels

Anastomosing channels

Microcysts

Microcysts

Delicate septae

Delicate septae

Tubules and signet rings

Tubules and signet rings

Entrapped cortex

Entrapped cortex


Lymphoid aggregates

Lymphoid aggregates

Calcification

Calcification

Infiltrative

Infiltrative

CK7

CK7

WT1

WT1

MelanA


MelanA


Electron microscopy description
Sample pathology report
  • Right adrenal gland, robotic adrenalectomy:
    • Adenomatoid tumor, 4.8 cm
    • Surgical margin, negative for tumor
Differential diagnosis
Board review style question #1


A 42 year old man presents for evaluation of right renal stones and is incidentally found to have a 4 cm mass in the left adrenal gland. Laboratory studies are within normal limits and he reports no symptoms other than right flank pain consistent with his known diagnosis. Adrenalectomy is performed and the pathology report subsequently confirms adenomatoid tumor of the adrenal gland (shown above). Positivity for which of the following immunostains (shown above) likely confirmed the diagnosis?

  1. CD31
  2. CD34
  3. CK5/6
  4. Inhibin
  5. MelanA
Board review style answer #1
C. CK5/6. Adenomatoid tumor is of mesothelial origin and as such expresses CK5/6. Adrenal cortical lesions express MelanA and inhibin, while vascular lesions express CD31 and CD34.

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Reference: Adenomatoid tumor
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