Skin nonmelanocytic tumor
Adnexal tumors - eccrine sweat glands
Chondroid syringoma


Topic Completed: 1 May 2015

Revised: 29 March 2019

Copyright: 2002-2019, PathologyOutlines.com, Inc.

PubMed Search: Chondroid syringoma [title]

Aravindhan Sriharan, M.D.
Sara C. Shalin, M.D., Ph.D.
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Cite this page: Sriharan A, Shalin SC. Chondroid syringoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/skintumornonmelanocyticchondroidsyringoma.html. Accessed July 21st, 2019.
Definition / general
Terminology
  • Other names include:
    • Apocrine mixed tumor
    • Eccrine mixed tumor
    • Mixed tumor of skin
    • Cutaneous mixed tumor
Epidemiology
Sites
  • Head and neck region involvement is common - nose is most common site here
  • Extremities are less common - axilla is most common site here
Prognostic factors
  • Malignant counterpart (malignant Chondroid Syringoma) does exist and should be ruled out on microscopic morphology
  • Some advocate a third category called "cutaneous mixed tumor with atypical features", for tumors with malignant cytology and no metastases (Am J Dermatopathol 1998;20:35)
Clinical features
  • Benign; rarely recurs
  • Most often seen in middle aged men; mean age at presentation is 48 years
  • Most commonly in nose, followed by cheek and upper lip
  • Face / head & neck > extremities, trunk or back
  • Calcification / ossification may occur
  • Typically small (0.5 - 3 cm) and painless
  • May mimic pilomatricoma
  • No specific findings on dermoscopy
Radiology description
  • Ultrasonography shows well encapsulated, hyperechoic mass with radiating, hypoechoic septae
  • Color Doppler shows vascularization of intervening septae
  • MRI shows peripheral high intensity signal with central low intensity signal on T1 weighted imaging
  • T2 weighted imaging shows heterogeneously mixed signal intensities (J Ultrasound Med 2007;26:1435)
  • Enhances avidly on post-gadolinium MRI (Radiopaedia)
  • In the few cases studied, radiography of malignant chondroid syringoma tends to show higher signal intensity than muscle on proton sequence, and high signal enhancement with focal intermediate signal on STIR (Short T1 inversion) (Australas Radiol 2001;45:240)
  • Findings are not highly specific for chondroid syringoma over other dermal and soft tissue neoplasms (Australas Radiol 2001;45:240)
Treatment
  • Surgical excision is curative
  • Recurrence of benign chondroid syringoma is rare
Case reports
Clinical images

Images hosted on other servers:

Left supraorbital swelling

Single well defined nodule

Atrophy and scarring on surface

Gross description
  • Nodular, circumscribed, nonulcerated with marked variation in size
  • Cut surfaces are tan-white, often with grossly apparent chondroid component
  • Slow growing, painless, firm, deep dermal to subcutaneous nodule
Gross images

Images hosted on other servers:

2 different apocrine mixed tumors (Source)

Microscopic (histologic) description
  • A well circumscribed but unencapsulated, multilobulated mass centered in deep dermis or subcutaneous fat, with a prominent chondroid or myxoid stroma enveloping benign bland appearing epithelial and myoepithelial cells that form secondary structures
  • Lobules are separated by fibrous septae of varying width
  • The secondary structures include glands and ducts, cysts, reticular lacelike networks, keratinous cysts and foci of squamous differentiation
  • Other cells present include plasmacytoid, low cuboidal, spindled, clear cell, cells with follicular and pilomatrical differentiation and mature adipocytes
  • Though typically chondromyxoid, the background may be focally hyaline
  • Mitoses are sparse
  • Importantly, necrosis is absent
  • May have eosinophilic globules with radiating fibrillary structures around their lumina, similar to mammary collagenous spherulosis
  • Major criteria for diagnosis are:
    1. A chondroid matrix
    2. Tubuloalveolar structures lined by a bilayered epithelium
    3. Ductal structures lined by a single epithelium
    4. Nests of polygonal cells
    5. The presence of keratinous cysts (Arch Dermatol 1961;84:835)
  • Satisfaction of all criteria is not necessary for diagnosis
  • Biphasic with both epithelial and stromal components
    • Epithelial: elongated branching tubular structures with two cell layers
      • Outer layer is cuboidal or columnar; inner layer is columnar with eosinophilic cytoplasm
      • "Decapitation" type secretion, often squamous metaplasia and basal nuclei
      • Often has areas of apocrine, follicular and sebaceous differentiation
      • Presence of any follicular or sebaceous features rules out PURE eccrine mixed tumor
      • Wide array of morphologies can be seen, with all types of differentiation along the folliculosebaceous unit
      • Occasional cases have neoplastic tubules connecting directly to normal follicular infundibulum
      • Follicular differentiation is the most common type of change in the epithelium and may include:
        • Keratinous cysts with infundibular keratinization
        • Isthmic epithelium
        • Hair bulbs with papillary mesenchyme
        • Matrical differentiation with basaloid, transitional and ghost cells
        • Trichohyaline granules
        • Vellous hair shafts
        • Anagen differentiation
      • Sebaceous differentiation may include single cells or islands of mature sebocytes
      • Metaplastic epithelial changes include clear cell change, columnar change, cytoplasmic vacuolization (may be abortive luminal differentiation), hobnailing, mucinous, oxyphilic, squamous
      • Metaplastic myoepithelial changes include clear cell change, collagenous spherulosis, hyaline cells, plasmacytoid cells, spindled cells
    • Stroma: chondroid, mucoid or fibrous
      • Metaplastic stromal changes include adipocytic, chondroid and osseous ametaplasia
      • Adipocytic metaplasia may be extensive; some adipocytes may have Lochkern nuclei with a single small vacuole indenting the nucleus that resemble lipoblasts
  • In contrast to eccrine mixed tumors, apocrine mixed tumors do not have clear cell change, cribriform areas, osseous metaplasia (prominent), physaliphorous-like cells, pseudorosettes
  • Benign tumors may have:
    • Asymmetry
    • Mild nuclear pleomorphism within the ductal component
    • Multinucleated, bizarre, hyperchromatic cells
    • Infiltrative or pushing borders
  • Features suggestive of malignancy include:
    • Severe atypia
    • Markedly increased cellularity
    • Increased mitotic rate
    • Destruction of surrounding tissue
    • Tumor necrosis
Microscopic (histologic) images

Contributed by Joel
Pinczewski, M.D., Ph.D.

Mixed tumor



Contributed by Angel Fernandez-Flores, M.D., Ph.D.

Various images



Images hosted on other servers:

Contributed by Aravindhan Sriharan, M.D. and J. Mike Magill, Jr., M.D.










Other images

Retiform, racemiform, solid and cribiform areas

Differentiation toward folliculosebaceous - apocrine unit

Metaplastic changes in the epithelium

Changes in the myoepithelial component

Stromal changes, depicting myxoid change

Cytology description
  • Many epithelial cells with bland nuclei in a chondromyxoid background
  • Marked nuclear pleomorphism and prominent nucleoli have been successfully used to differentiate malignant from benign chondroid syringoma on fine needle aspirate (Acta Cytol 1998;42:1155)
  • Criteria suggested for definitive diagnosis of chondroid syringoma on fine needle aspirate (Acta Cytol 2010;54:183):
    1. Fibrillary chondromyxoid background
    2. Prominent cellular component of epithelial and myoepithelial cells
    3. Absence of atypia and tumor diathesis
Cytology images

Images hosted on other servers:

Cellular smear

Cellular aspirates

Positive stains
Negative stains
Electron microscopy description
  • 2 distinct populations of cells, epithelial and myoepithelial
  • Epithelial cells are darker, cuboidal to polyhedral, and have:
    • Hemidesmosomes connecting to other epithelial cells
    • Tonofilaments which, in some cases, form a ring around the nuclei
    • Conspicuous intracytoplasmic lumen formation with numerous microvilli
    • Nuclei with invaginated membranes and chromatin condensed immediately under the nucleolemma
  • Myoepithelial cells are lighter, low cuboidal, and:
    • Lack desmosomes affixing to other myoepithelial cells
    • Have hemidesmosomes connecting to epithelial cells
    • Have fine fibrillary interstitital material interspersed between successive myoepithelial cells
    • Have signficiantly fewer organelles than epithelial cells
    • Have large central 50 Angstrom cytoplasmic filaments with few, peripheral scattered organelles
  • Cells within cartilage on light microscopy are identical to true chondrocytes on electron microscopy (Ultrastruct Pathol 1984;6:153)
  • Transitional cells, with electron microscopic features between chondrocytes and epithelial cells, are also found (Ultrastruct Pathol 1984;6:153)
  • Hyaline / plasmacytoid cells have ultrastructural features of myoepithelial cells with cytoplasmic intermediate filaments (Pathologica 1997;89:540)
Molecular / cytogenetics description
Differential diagnosis
  • Apocrine mixed tumor: has characteristic decapitation secretion
  • Cutaneous chondroma: lacks the epithelial and myoepithelial elements
  • Malignant mixed tumor: necrosis, infiltrative growth, marked pleomorphism and greater cellularity
  • Metastatic carcinoma: can often be distinguished based on immunohistochemistry and cytologic features of malignancy
  • Parachordoma: rare, no true ducts, actin negative, presence of physalliferous cells, arises adjacent to tendon and synovium in extremities
    • Often considered a variant of myoepithelioma
  • Collagenous spherulosis: more common in breast, lumina contain dense eosinophilic secretion, no biphasic appearance
  • Hidradenoma papilliferum: no chondroid matrix, not biphasic
  • Myopeithelioma / adenomyoepithelioma of the skin: more common on extremities, myoepithelial areas should predominate, lacks luminal epithelial cells, negative for cytokeratin and CEA
  • Other adnexal tumors with apocrine differentiation
Additional references
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