Papillary Hidradenoma

Slide 1 · Papillary hidradenoma

Vulvar glandular tumor: clinicopathologic recognition, architecture and differential diagnosis

Dr Abu Suraih Sakhri

MBBS, MD (Pathology)

www.abusuraihsakhri.com

Slide 2 · What the learner should be able to do

Recognize the typical location and appearance of papillary hidradenoma.

Explain the two-cell-layer architecture of this benign glandular tumor.

Distinguish papillary hidradenoma from malignant and other papillary vulvar lesions.

Use morphology before considering targeted ancillary stains.

Slide 3 · Glandular neoplasia in the vulva

The anatomic context

Vulvar skin contains modified apocrine and mammary-like secretory structures.

Glandular lesions are distinct from epithelial squamous lesions.

Two Robbins exemplars

Papillary hidradenoma: Circumscribed glandular nodule.

Extramammary Paget disease: Intraepidermal malignant glandular cells.

Slide 4 · Entity, nomenclature and behavior

Papillary hidradenoma is also termed hidradenoma papilliferum.

It is a benign epithelial adnexal neoplasm with glandular/apocrine differentiation.

Its defining histology is a circumscribed papillary lesion with luminal and myoepithelial layers.

Slide 5 · Clinical-to-microscopic diagnostic logic

Vulvar nodule

Biopsy or excision

Circumscribed papillary glands

Luminal + basal layers

Benign papillary hidradenoma

Slide 6 · Why a benign lesion may suggest carcinoma

The nodule may ulcerate and bleed at the skin surface.

Ulceration is clinically alarming but not synonymous with malignancy.

Histology determines whether tumor growth is circumscribed or infiltrative.

Cytologic atypia and preservation of a myoepithelial layer refine the distinction.

Slide 7 · What does the vulvar glandular background mean?

Robbins framework

Modified apocrine sweat glands are present in vulvar skin.

Breast-like glandular differentiation explains familiar epithelial patterns.

Interpretive caution

Mammary-like anogenital glands are discussed in later studies.

Do not equate a breast-type morphology with a primary breast lesion.

Slide 8 · Likely site: Labia and interlabial folds

Lesions most often on the labia majora or interlabial folds.

The lesion is centered in the vulvar cutaneous/adnexal compartment.

A clinical site description helps the histopathologist interpret glandular morphology.

Slide 9 · Usual distribution versus less typical sites

Common setting

Solitary nodule of the vulva.

Labial or adjacent anogenital region.

Less typical presentations

Other anogenital sites and rare ectopic cutaneous sites have been reported.

An unusual site requires careful morphology-based confirmation.

Slide 10 · Tumor sits beneath the surface

Surface epidermis

Well-circumscribed dermal nodule

Schematic — not a histologic specimen

A compact, dermal-based glandular proliferation is characteristic.

The overlying epidermis is usually not directly continuous with the tumor.

Surface erosion can occur without infiltrative tumor biology.

Slide 11 · Clinical morphology: Circumscribed nodule

Papillary hidradenoma often presents as a small, sharply defined lesion.

The surface may appear pink or red; A clinically intact surface is possible.

It is not reliably diagnosed by naked-eye inspection alone.

Slide 12 · Symptoms: Present or absent

Possible incidental presentation

Slow growth or asymptomatic course may prompt delayed evaluation.

A well-demarcated nodule may be noticed during examination.

Symptomatic presentation

Ulceration or bleeding can trigger concern for carcinoma.

Discomfort or irritation warrants examination but is not histotype-specific.

Slide 13 · What the 45-case series actually reports

Wang and colleagues described 45 vulvar lesions from a multi-institutional series.

Their observed tumor sizes were 0.3–2.0 cm.

Reported clinical colors included pink and red.

These are descriptive findings from that cohort, not population prevalence estimates.

Slide 14 · A nodule and an ulcer are different observations

Nodule assessment

Define size, site, mobility and clinical margins.

Document whether a discrete mass is present.

Surface assessment

Note ulceration, crusting or focal bleeding separately.

A disrupted surface does not determine the lesion’s histologic grade.

Slide 15 · Why clinical pattern recognition is insufficient

Multiple benign vulvar conditions form nodules or papillary lesions.

Malignancy also can present as a focal ulcerated mass.

Location and appearance narrow the differential but cannot establish the diagnosis.

Slide 16 · A practical diagnostic sequence

Describe lesion and site

Obtain tissue

Assess architecture on H&E

Confirm epithelial bilayer

Resolve atypical features

Slide 17 · Tissue diagnosis: What should be documented

Exact anatomic location and clinical impression.

Whether the specimen is incisional tissue or an excised mass.

Surface ulceration and gross circumscription where assessable.

Presence or absence of representative lesion at the deep and peripheral edges.

Slide 18 · Gross interpretation: Outline and contents

Supporting benign architecture

A sharply circumscribed nodular outline.

A localized lesion rather than a diffuse epithelial plaque.

What gross inspection cannot prove

Papillary spaces and a myoepithelial layer require microscopy.

A benign-looking margin alone cannot exclude an unexpected carcinoma.

Slide 19 · Low-power recognition: An organized border

Smooth peripheral outline

Adjacent

Stroma

Peripheral assessment at low power

Schematic — not a histologic specimen

The lesion is typically well circumscribed within the dermis.

Fibrous tissue can be compressed around the lesion (pseudocapsule).

Evaluate the entire periphery for an unexpectedly infiltrative interface.

Slide 20 · Low power: Tubular and papillary complexity

Tubules, luminal spaces and folded fronds

Schematic — not a histologic specimen

Tubules and dilated gland-like spaces vary in size.

Elongated papillary fronds project into luminal spaces.

A branching or labyrinthine configuration can still represent benign architecture.

Slide 21 · Papillary fronds: Epithelial surfaces around cores

Luminal epithelium

Stromal core

Papillary projection into a lumen

Schematic — not a histologic specimen

A papilla projects into a lumen from its supporting connective tissue.

Broad papillae may contain recognizable stromal or fibrovascular cores.

Identify luminal lining cells separately from subjacent myoepithelial cells.

Slide 22 · Cystic and glandular spaces

Tubules, luminal spaces and folded fronds

Schematic — not a histologic specimen

Secretory lumina are lined by a luminal epithelial population.

Papillary structures fold into some lumina, giving a complex glandular profile.

Architectural complexity alone is not evidence of stromal invasion.

Slide 23 · The diagnostic two-cell-layer motif

Lumen

Columnar luminal cells

Flattened basal myoepithelial cells

Schematic — not a histologic specimen

Upper layer: Columnar secretory cells facing the lumen.

Lower layer: Flattened or cuboidal myoepithelial cells along the basal interface.

Both layers can be followed around benign papillary profiles.

Slide 24 · Luminal cells and basal myoepithelial cells

Luminal compartment

Tall columnar glandular cells.

Secretory differentiation; Luminal or apical cytoplasm.

Basal compartment

Flattened/cuboidal myoepithelial elements.

An epithelial–stromal interface maintained around glands.

Slide 25 · The luminal cell layer

Lumen

Columnar luminal cells

Flattened basal myoepithelial cells

Schematic — not a histologic specimen

Tall, often columnar cells border a gland lumen.

The apical surface may exhibit apocrine-type secretory changes.

Bland cytology supports benign interpretation alongside architecture.

Slide 26 · The myoepithelial layer

Lumen

Columnar luminal cells

Flattened basal myoepithelial cells

Schematic — not a histologic specimen

Basal cells lie outside the secretory columnar layer.

These elements are characteristic of secretory adnexal gland structures.

Recognizing them is more meaningful than counting layers in isolation.

Slide 27 · Apocrine secretion: What to look for

Lumen

Apical secretory protrusions

Flattened basal myoepithelial cells

Schematic — not a histologic specimen

Apical snouts or focal decapitation-type secretion may be seen.

This suggests secretory/apocrine differentiation of luminal cells.

The feature is supportive rather than a stand-alone diagnostic criterion.

Slide 28 · Cytologic findings supporting benignity

Reassuring features

Relatively orderly luminal epithelium.

Minimal cytologic atypia and preserved layering.

No convincing destructive infiltration.

Concerning departure

Striking nuclear atypia or atypical mitoses.

Tumor necrosis or irregular infiltrative glands.

Loss of an organized epithelial–myoepithelial profile.

Slide 29 · Tumor–stroma interface

Smooth peripheral outline

Adjacent

Stroma

Peripheral assessment at low power

Schematic — not a histologic specimen

A compact lesion has a boundary recognizable at scanning magnification.

Compression of adjacent collagen may create a pseudocapsule.

Do not mistake a curved papillary fold for infiltration into stroma.

Slide 30 · The surface and tumor can be disconnected

Typical relationship

A dermal tumor without direct continuity with the epidermis.

The epidermis may be preserved or locally eroded.

Different diagnostic pattern

An exophytic lesion continuous with epidermis suggests a different papillary process.

Intraepidermal spread of malignant glandular cells suggests Paget disease.

Slide 31 · Why Robbins invokes intraductal papilloma

Shared architecture

Papillae and glandular spaces.

Luminal epithelium plus an underlying myoepithelial population.

Important distinction

Breast papilloma is located within a mammary duct.

Papillary hidradenoma arises in vulvar glandular/adnexal tissue.

Slide 32 · Breast analogy: Fibrovascular branching

Luminal epithelium

Stromal core

Papillary projection into a lumen

Schematic — not a histologic specimen

Intraductal papilloma as branching papillae inside a duct.

A central fibrovascular core is a useful architecture concept.

The epithelial bilayer—not the organ name—explains the resemblance.

Slide 33 · Structural comparison: Vulvar and breast papillomas

Feature

Papillary hidradenoma

Intraductal papilloma

Usual site

Vulvar dermis / anogenital skin

Mammary duct

Arrangement

Circumscribed papillary/tubular tumor

Papillary tumor within duct

Epithelial support

Luminal + myoepithelial layers

Luminal + myoepithelial layers

Teaching role

Vulvar glandular differential

Morphologic comparator

Slide 34 · H&E: A reproducible reading order

First: Identify whether the lesion is dermal and circumscribed.

Second: Search for cystic spaces and papillary fronds.

Third: Identify columnar luminal and basal myoepithelial layers.

Fourth: Evaluate atypia, mitoses, necrosis and peripheral invasion.

Slide 35 · High power: Avoid mistaking folded glands for atypia

Repeated gland profiles may reflect section plane

Tangential cut

Schematic — not a histologic specimen

A tortuous gland may intersect the section plane many times.

Distinguish a genuine solid epithelial expansion from a tangential fold.

Follow papillary cores and cell-layer polarity across adjacent profiles.

Slide 36 · When ancillary stains add value

Routine H&E is generally sufficient in classic cases.

Immunohistochemistry can clarify the luminal and myoepithelial compartments.

Select markers to test a specific problem rather than stain indiscriminately.

Slide 37 · Luminal immunophenotype: Supportive markers

Marker

Expected use

Interpretive limit

CK7

Demonstrates glandular luminal epithelium

Not specific for this tumor

EMA / CEA

Support glandular differentiation

Not proof of benignity

GCDFP-15

Supports apocrine differentiation

Can be focal

ER / PR

May be expressed by luminal cells

Variable; Not a requirement

Slide 38 · Myoepithelial markers: Basal compartment

Marker

Compartment illustrated

Caution

P63

Nuclear staining in basal myoepithelial cells

Interpret with location

S100

May label myoepithelial cells

Not specific by itself

Smooth muscle actin

Supports basal myoepithelial phenotype

Requires morphology correlation

CD10

Additional reported basal marker

Not uniquely diagnostic

Slide 39 · Why an IHC panel is not the diagnosis

Helpful result

CK7-positive luminal cells.

P63-positive basal cells around glands.

Architecture remains circumscribed and orderly.

Unhelpful shortcut

One positive glandular stain cannot classify all papillary lesions.

A focal/negative apocrine stain cannot alone exclude a classic tumor.

Slide 40 · Problem-solving use of IHC

H&E architecture

Question: Is basal layer intact?

Choose a myoepithelial marker

Correlate basal pattern with glands

Integrated interpretation

Slide 41 · The essential positive morphologic constellation

Dermal-based, circumscribed nodule.

Branching tubules, papillae and occasional cystic lumina.

Luminal columnar cells overlying basal myoepithelial cells.

Absence of overt malignant cytology or destructive stromal invasion.

Slide 42 · Atypical findings require a broader diagnosis

Expected features

Orderly two-cell-layer glands.

Pushing/circumscribed border.

No marked atypia or conspicuous atypical mitoses.

Escalation features

Infiltration, marked nuclear polymorphism, conspicuous mitoses.

Extensive necrosis or unexpectedly solid expanses.

Correlate with sampling and additional histology.

Slide 43 · Papillary hidradenoma versus syringocystadenoma

Characteristic

Papillary hidradenoma

Syringocystadenoma papilliferum

Surface contact

Usually no epidermal connection

Typically connected to surface

Dominant pattern

Circumscribed dermal papillary glands

Papillary lesion with surface involvement

Stromal reaction

May show fibrous pseudocapsule

Plasma cells often in papillary cores

Useful clue

Two-layer glandular neoplasm

Surface continuity + plasma cells

Slide 44 · Bartholin cyst: Clinically adjacent, morphologically different

Bartholin duct obstruction

Cystic process related to the Bartholin duct.

Interpret by ductal/cyst lining and clinical site.

Papillary hidradenoma

Solid–cystic papillary glandular tumor.

Recognizable luminal + myoepithelial layered proliferation.

Slide 45 · Squamous papilloma is not a glandular papilloma

Benign squamous papilloma

Papillary/exophytic lesion covered by squamous epithelium.

No glandular secretory bilayer as defining structure.

Papillary hidradenoma

Papillae inside glandular lumina, often in dermis.

Columnar secretory lining plus basal myoepithelial cells.

Slide 46 · Condyloma: HPV-related squamous rather than glandular

Condyloma acuminatum

Exophytic treelike squamous fronds.

Koilocytic change can be present.

Related to low-risk HPV, mainly 6 and 11.

Papillary hidradenoma

Dermal glandular papillary neoplasm.

Two-layer secretory and myoepithelial architecture.

Do not presume an HPV-driven process.

Slide 47 · Extramammary Paget disease has a different compartment

Paget disease

Malignant pale glandular cells dispersed in epidermis.

Often visible as erythematous pruritic crusted plaque.

Papillary hidradenoma

Localized dermal nodule.

Organized glands/papillae with basal myoepithelial cells.

Slide 48 · Vulvar adenocarcinoma: Infiltration is central

Benign glandular papillary tumor

Smooth boundary; Orderly bilayer.

Little atypia; No destructive tissue invasion.

Suspicious adenocarcinoma

Infiltrative margins, atypical glands and cytologic malignancy.

Myoepithelial investment often absent in invasive glandular areas.

Slide 49 · A focused differential decision table

Main question

Finding favoring hidradenoma

Finding prompting alternative

Is this squamous?

True glandular luminal structures

Squamous-lined surface fronds

Is it surface connected?

Usually dermal and disconnected

Epidermal continuity / Paget cells

Is a basal layer present?

Myoepithelial layer preserved

Absent basal layer with infiltration

Is there destructive growth?

Circumscribed or pushing outline

Irregular infiltrative border

Slide 50 · Diagnostic pitfalls: Four common traps

Ulceration is mistaken for evidence of invasion.

An arborizing glandular pattern is overcalled as carcinoma.

A single positive immunostain is treated as disease-specific.

A superficially sampled lesion cannot be assessed for circumscription.

Slide 51 · Clinical management: Link action to diagnosis

Definitive histology commonly follows local removal of the lesion.

For a classic completely excised benign lesion, routine follow-up can be individualized.

Persistent, recurrent or atypical lesions warrant reevaluation and possible resampling.

Do not apply carcinoma treatment pathways to a benign papillary tumor.

Slide 52 · An excision specimen answers two questions

Classification

Does the morphology support papillary hidradenoma?

Are any atypical or invasive components identified?

Completeness

Does the specimen include the lesion boundary?

Can margin involvement be meaningfully assessed?

Slide 53 · What a useful pathology report conveys

Recognizable diagnostic term: Papillary hidradenoma (hidradenoma papilliferum).

Location, size and specimen type when supplied.

Any ulceration, unusual atypia or invasive component if present.

Margin status only where specimen orientation and sampling support it.

Slide 54 · Case 1 · an asymptomatic vulvar nodule

Clinical or microscopic vignette

A small, well-defined labial nodule is removed. The section shows papillary glands within the dermis; Luminal columnar cells have a basal myoepithelial layer.

Which feature most strongly supports the proposed diagnosis?

An organized papillary glandular proliferation with an intact two-cell-layer lining supports papillary hidradenoma.

Slide 55 · Case 2 · the ulceration trap

Clinical or microscopic vignette

A vulvar nodule has a focal ulcerated surface and is referred as “rule out carcinoma.” Histology shows a circumscribed papillary tumor with bland epithelial cells.

Does ulceration establish malignant transformation?

No. Papillary hidradenoma may ulcerate and clinically resemble carcinoma; Invasion and cytology must be assessed.

Slide 56 · Case 3 · a surface-connected papillary lesion

Clinical or microscopic vignette

A papillary lesion is directly continuous with the epidermis, and several papillary cores show a conspicuous plasma-cell infiltrate.

Which competing diagnosis should be prioritized?

Syringocystadenoma papilliferum is favored over typical papillary hidradenoma by the surface continuity and plasma-cell-rich cores.

Slide 57 · Case 4 · stains in context

Clinical or microscopic vignette

A dermal papillary glandular tumor is CK7 positive in the luminal compartment and p63 positive at the basal interface. The periphery is circumscribed.

What does this integrated pattern support?

The findings support a two-layer glandular adnexal lesion, consistent with papillary hidradenoma in the correct morphologic context.

Slide 58 · Case 5 · the missing layer

Clinical or microscopic vignette

A vulvar glandular lesion contains markedly atypical epithelial cells and irregular glands infiltrating dermal collagen; Myoepithelial markers do not outline many abnormal glands.

What is the safest diagnostic next step?

Do not force a benign diagnosis. Evaluate for an invasive adenocarcinoma or another malignant glandular neoplasm with comprehensive sampling and correlation.

Slide 59 · Synthesis: Recognize a pattern, not a single clue

A circumscribed vulvar papillary glandular tumor is the clinical-pathologic starting point.

Luminal columnar cells and basal myoepithelial cells provide the strongest structural signature.

Ulceration is compatible with benignity; Infiltrative growth and marked atypia require escalation.

Use IHC as morphology-directed support, not as a replacement for architecture.

Slide 60 · Three-minute final recognition checklist

Evaluation level

Question

Target observation

Clinical

Where is the lesion?

Labial / interlabial nodule

Low power

How does it interface with stroma?

Circumscribed dermal tumor

Intermediate

Which architecture dominates?

Arborizing papillae and tubules

High power

What lines each papilla?

Columnar luminal + basal myoepithelial cells

Safety check

Any malignant discrepancy?

Assess invasion / atypia / necrosis

Slide 61 · Selected references

Robbins, Cotran & Kumar. Pathologic Basis of Disease. 11th ed. (2026). Chapter 22, pp. 901–903 (Fig. 22.9); Chapter 23, Fig. 23.9.

Cheng H, Lamont D, Emanuel P. Hidradenoma papilliferum pathology. DermNet (2013). dermnetnz.org/topics/hidradenoma-papilliferum-pathology

Wang L, Chen G, Jiang J, et al. Vulvar Hidradenoma Papilliferum. Int J Gen Med. 2024;17:663–667. doi:10.2147/IJGM.S449102

Srajer V, et al. Vulvar hidradenoma papilliferum: A case report including dermatologic and histopathologic findings. Int J Gynaecol Obstet. 2025. doi:10.1002/ijgo.70199