Sweat gland neoplasms

Published on 08/03/2015 by admin

Filed under Dermatology

Last modified 22/04/2025

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Chapter 5

Sweat gland neoplasms

Dirk M. Elston

Blue sweat gland tumors differentiate towards the secretory portion of the sweat gland. Red sweat gland tumors differentiate towards the sweat duct. Sweat duct tumors often demonstrate clear cell change. Most sweat gland tumors can show at least focal decapitation secretion, suggesting they are capable of apocrine differentiation.

Cylindroma (turban tumor)

Key features

• Islands of blue cells with little cytoplasm

• Dark and pale blue nuclei present

• Jigsaw-puzzle pattern

• Islands outlined by a deeply eosinophilic basement membrane

• Deeply eosinophilic hyaline droplets may be noted in islands

• Often inherited and multiple on the scalp

Fig 5-1 Cylindroma

Spiradenoma

Key features

• Larger round islands of blue cells with little cytoplasm

• Dark and pale blue nuclei present

• Islands peppered with black lymphocytes

• Deeply eosinophilic hyaline droplets may be noted in islands

• Usually solitary

Spiradenomas and cylindromas are closely related tumors. Both differentiate towards the secretory portion of the sweat gland. Hybrid tumors occur. Spiradenomas are usually sporadic and solitary, while cylindromas are multiple, inherited, and may occur together with trichoepitheliomas. Spiradenomas are inflamed (lymphocytes) and spontaneously tender.

Fig 5-2 Spiradenoma

Table 5-1

Characteristics of cylindroma versus spiradenoma

Characteristic	Cylindroma	Spiradenoma
Blue cells with little cytoplasm	Yes	Yes
Dark and pale blue nuclei	Yes	Yes
Peppered with black lymphocytes	No	Yes
Hyaline droplets in nests	Yes	Yes
Jigsaw-puzzle pattern	Yes	No
Deeply eosinophilic basement membrane	Yes	No
Inheritance	Autosomal dominant	Sporadic
Tender	No	Yes

Spiradenocarcinoma

Key features

• Rare

• Occurs in long-standing spiradenomas

• Atypia, mitoses, and necrosis

Fig 5-3 Spiradenocarcinoma

Syringocystadenoma papilliferum

Key features

• Opens to surface

• Blue papillary fronds extending upward into clear spaces: “fjords and fronds”

• Decapitation secretion

• Plasma cells

Syringocystadenoma papilliform (SPAP) differentiates towards the secretory portion of the sweat gland. SPAP opens to the surface, which looks as though one could slide into it. Plasma cells are typically present in the mesenchymal core of each frond. Clinically, they appear as raised warty plaques on the head or neck. One-third of cases occur within nevus sebaceus.

Fig 5-4 Syringocystadenoma papilliferum

Hidradenoma papilliferum

Key features

• Blue dermal nodule with branching cystic spaces

• Papillary fronds

• Decapitation secretion

Hidradenoma papilliferum (HPAP) usually presents clinically as a vulvar dermal nodule, but occasionally presents on a breast, eyelid, or ear. Histologically, HPAP is a maze-like dermal nodule, which looks as though one could hide in it. The arborizing pattern of blue fronds demonstrates decapitation secretion. Like SPAP, it differentiates towards the secretory segment.

Papillary digital carcinoma (aggressive digital papillary adenocarcinoma)

There can be significant histologic similarities to hidradenoma papilliferum. All digital papillary tumors should be considered carcinomas.

Fig 5-5 Hidradenoma papilliferum

Fig 5-6 Papillary digital carcinoma

Mucinous carcinoma

Key features

• Islands of blue cells surrounded by mucin (“blue islands floating in a sea of snot”)

• Primary cutaneous mucinous carcinoma and metastatic mucinous carcinoma look identical

Mucinous carcinoma can be primary in the skin, or can be metastatic from a primary cancer of the breast or gastrointestinal tract. Imaging studies may be required.

Fig 5-7 Mucinous carcinoma

Syringoma

Key features

• Paisley-tie pattern of tadpole-shaped ducts

• Ample pink cytoplasm

• Dense red sclerotic stroma

• Tumor is small and round

Syrinx refers to a pipe or duct. Syringomas usually appear as small papules on the eyelids. They are especially common in Asian women and in children with Down’s syndrome. Eruptive syringomas typically occur on the chest, back, or penis of a dark-skinned patient. Eruptive syringomas appear as small hyperpigmented papules with no tendency to coalesce.

Fig 5-8 Syringoma

Fig 5-9 Clear cell syringoma

Clear cell syringoma

Key features

• Paisley-tie pattern of tadpole-shaped ducts

• Clear cells containing abundant glycogen

• Dense red sclerotic stroma

• Tumor is small and round

• Associated with diabetes mellitus

Microcystic adnexal carcinoma

Microcystic adnexal carcinoma (MAC) typically presents as a firm plaque on the upper lip, medial cheek, or chin. Histologically, they have a paisley-tie appearance with dense red sclerotic stroma, and must be differentiated from syringoma, morpheaform basal cell carcinoma, and desmoplastic trichoepithelioma.

Fig 5-10 Microcystic adnexal carcinoma

Table 5-2

Characteristics of microcystic adnexal carcinoma versus syringoma

Characteristic	Microcystic adnexal carcinoma	Syringoma
Paisley-tie pattern	Yes	Yes
Stroma	Red, sclerotic	Red, sclerotic
Horn cysts	Common	May occur
Size	Large	Small
Shape	Infiltrative	Round
Perineural extension	Yes	No
Basaloid islands	+/−	No
Clinical appearance	Plaque on upper lip, cheek, chin	Small papules on eyelids or eruptive papules

Table 5-3

Characteristics of microcystic adnexal carcinoma versus morpheaform basal cell carcinoma

Characteristic	Microcystic adnexal carcinoma	Morpheaform basal cell carcinoma
Paisley-tie pattern	Throughout tumor	Sometimes superficially
Stroma	Red, sclerotic	Red, sclerotic
Horn cysts	Common	Occasional
Deeply invasive	Yes	Yes
Perineural invasion	Yes	Yes
Clinical appearance	Plaque on upper lip, cheek, chin	Scar-like

Table 5-4

Characteristics of microcystic adnexal carcinoma versus desmoplastic trichoepithelioma

Characteristic	Microcystic adnexal carcinoma	Desmoplastic trichoepithelioma
Paisley-tie pattern	Yes	Yes
Stroma	Red, sclerotic	Red, sclerotic
Horn cysts	Common	Common
Calcification	Rare	Common
Lymphoid aggregates	Typical	Rare
Perineural extension	Yes	No
Central dell	No	Typical
Clinical appearance	Plaque on upper lip, cheek, chin	Firm doughnut

Sclerosing sweat duct carcinoma

Sclerosing sweat duct carcinoma has been described as the “syringoma from hell.” Although small fields closely resemble syringoma, the tumor is deeply invasive and demonstrates perineural invasion. The clinical appearance is identical to that of a MAC. Perivascular nodular lymphoid aggregates are common in the tumor stroma.

Fig 5-11 Sclerosing sweat duct carcinoma

Fig 5-12 Hidrocystoma

Hidrocystoma

Key features

• Simple cyst

• Lined by cuboidal or columnar cells

• Decapitation secretion may be noted

Hidrocystomas typically appear as bluish translucent papules on the cheeks or eyelids.

Mixed tumor (chondroid syringoma)

Key features

• Sweat ducts with ample pink cytoplasm embedded in a mesenchymal stroma

• Secretory elements with blue nuclei and little cytoplasm may be present

• Cartilaginous differentiation common in stroma

• Bone formation may occur

Small tubular type

Key features

• Sweat ducts with ample pink cytoplasm embedded in a mesenchymal stroma

• Cartilaginous differentiation common in stroma

• Small tubules resemble those of a syringoma

Branching alveolar type

Key features

• Sweat ducts embedded in a mesenchymal stroma

• Cartilaginous differentiation common in stroma

• Tubules quite long, with a branching and alveolar pattern

• Decapitation secretion may be seen

While the small tubular type of chondroid syringoma differentiates towards the sweat duct, the branching alveolar type shows differentiation towards both the secretory segment and duct. Mucin within the stroma is sulfated, giving it a deep gray-blue cartilaginous hue.

Pearl

Metachromatic stains for mucin include toluidine blue, methylene blue, and Giemsa (methylene blue plus eosin). Alcian blue and colloidal iron are not metachromatic stains. Chondroitin sulfate stains with Alcian blue and toluidine blue at both high and low pH.

Fig 5-13 Mixed tumor, small tubular type

Fig 5-14 Mixed tumor, branching alveolar type

Malignant mixed tumor (malignant chondroid syringoma)

Key features

Acrospiromas

Key features

• Differentiate towards the acrosyringium (the intraepidermal portion of the sweat duct)

• Cuboidal cells with ample pink cytoplasm

• Tendency towards clear cell degeneration

• Cuticle-lined ducts

• Pink sweat may be seen within ducts

Fig 5-15 Malignant mixed tumor

Acrospiromas comprise a large family of sweat gland tumors that includes poromas, hidradenomas, dermal duct tumors, and hidroacanthoma simplex. They are all composed of cells that resemble those of the acrosyringium. They all demonstrate duct differentiation within tumor islands. Hybrid forms are common.