Sweat Gland Differentiation

Microcystic adnexal carcinoma (MAC) shows dual differentiation into sebaceous gland and sweat gland structures. There are no known causative factors, although in some cases there is history of ionizing radiation exposure. The incidence in men and women is approximately equal and the median age at presentation is 65 years (range, 11-82). MAC presents clinically as a nodule, plaque, or cyst that grows slowly over years (173). The lesion is markedly indurated and has surface telangiec-tasias. It rarely undergoes ulceration. The main clinical differential diagnosis is mor-pheaform BCC, SCC, dermatofibrosarcoma protuberans (DFSP), and other adnexal tumors. MAC metastasizes to lymph nodes only occasionally but may directly invade bone in advanced cases. On histological examination there is a desmoplastic stroma, nests and cords of basaloid cells with ductal structures, and keratin-filled cysts. MAC is a dermal tumor, the epidermis is rarely involved, and there is peri-neural involvement in 80% of cases. IHC stains show CEA, S-100, and CF-1. MAC is difficult to eradicate due to marked subclinical extension and perineural involvement. The recurrence rate is 47% after surgical excision with margins up to 5 cm. Current recommendations include preoperative CT scan and MRI assessment of extension followed by Mohs' micrographic surgery (174).

Malignant eccrine spiradenoma (MES) shows differentiation toward eccrine intradermal ductal cells or secretory cells and affects people 50 years and older. It presents clinically as a sudden change in color or size of a pre-existing benign eccrine spiradenoma. Ulceration may also occur. Approximately 40% of cases are located on the upper extremities. Metastases occur only in lesions larger than 2 cm in diameter, usually to lymph nodes or lungs. Histological examination shows cords of basophilic cells with compact nuclei. Lobules are surrounded by a hyaline fibrous capsule (175). IHC stains show CEA, EMA, CK, and S-100. Surgical excision with 1-2 cm margins is the treatment of choice (176). Elective lymph node dissection should be considered. For clinically positive nodal disease, a therapeutic lymph node dissection is performed. Radiation therapy was not effective in two case reports.

Eccrine porocarcinoma (EPC) derives from the intraepidermal portion of the eccrine duct or acrosyringium. There are no known causative factors. Some 30-50% of cases originate from malignant transformation of pre-existing benign o eccrine poromas. PC affects people older than 50 years and there is a slight predominance in women. The tumor is more frequent in whites (85%) than in Japa- |

nese (14%). The most frequent location is the lower extremities (50%), legs (25%), o foot (14%), and thigh (12%). Malignant transformation of a benign poroma is man- §

ifested by ulceration, bleeding, or sudden growth (177). Metastases occur in 20% of @

cases, usually with tumors larger than 1 cm in diameter. Metastases involve the lymph nodes, lungs, retroperitoneum, bone, and liver. Mortality is approximately 68%. On histopathological examination, there are intraepidermal nests of basaloid cells, absent keratinization, and small clefts within tumor islands. IHC stains show positive reaction to CEA, EMA, and CK. Both surgical excision and Mohs' micrographic surgery offer cure rates of 85% (178). The latter is preferred for recurrent lesions. If PC spreads to lymph nodes, cure is difficult. Therapeutic lymph node dissection is successful in only 17% of cases, with 83% developing distant metastases. There are no data on ELND. Chemotherapy has variable response rate for distant metastatic disease.

Malignant clear cell hidradenoma (MCCH) is considered to be the malignant counterpart of eccrine acrospiroma. It is a rare tumor, accounting for only 6% of malignant eccrine neoplasms. There are no known risk factors. The tumor has an equal gender distribution, and patients have an average age of 52 years. MCCH presents as a nonspecific nodule or plaque, usually 3 cm in diameter or smaller. The lesion is red with surface telangiectasias. Ulceration is rare. At least 49% occur on the scalp or face, followed by acral sites in 28%, and trunk 23% (179). On histolo-gical examination, there are lobules with two cell populations. Centrally located are clear cells containing glycogen; basophilic spindle cells are found at the periphery. A characteristic feature is the presence of prominent squamous proliferation. Like most eccrine tumors, IHC staining shows EMA, CEA and CK positivity. MCCH tends to recur in 50% of cases due to extensive subclinical extension and perineural involvement (180). Radiation therapy should be avoided because it has been associated with more aggressive behavior. Metastases involve lymph nodes (40%) or distant sites. Recurrent tumors or MCCH with nodal involvement is best approached with Mohs' surgery followed by chemotherapy (doxorubicin, 5-FU, cisplatin). Distant metastatic disease is uniformly fatal despite chemotherapy.

Eccrine mucinous carcinoma (EMC) is derived from the eccrine secretory coil. It is a rare tumor that predominates in Whites (65%) and men (66%). Patient's median age is 63 years, ranging from 50 to 70. The lesion is usually single and asymptomatic. Approximately 75% of cases affect the eye, face, or scalp. It presents as a clinically translucent papule or nodule with a red or blue hue (181) resembling BCC or pyogenic granuloma. Most EMCs follow an indolent course, but metastases may occur in 10% of cases (3% of eye tumors but 38% of truncal lesions). Meta-static spread is to regional lymph nodes with only occasional reports of distant metastases. Histopathological examination reveals basaloid cells within mucinous stroma. Cells are uniform in size and shape with few mitotic figures. IHC stains are positive for EMA, CEA, and CK. Traditional surgical excision with 2 cm margins has a 28% recurrence rate (182). Mohs' surgery may offer a better control rate, -g especially for eyelid tumors and recurrent cases. Regional nodal disease is treated with therapeutic lymph node dissection. The role of ELND is unknown. Distant metastases fail to respond to both radiation therapy and chemotherapy.

Malignant chondroid syringoma (MCS) originates from apocrine structures. It differentiates into sweat gland and chondroid elements. Most lesions develop de novo and not from benign counterparts. At least two-thirds of cases occur in women |

(183). Age ranges from 13 to 89, with an average of 52 years. The most frequent loca- o tion is the lower extremity (35%) followed by the upper extremity (20%), head and §

neck (25%), and trunk (15%). MCS presents clinically as firm nodules that may @

ulcerate. Approximately 80% are painful. Histological examination shows lobules containing epithelial and mesenchymal elements (chondrocytes) with variable pseudocapsule. Wide local excision results in a 50% recurrence rate and 45% metastases to lymph nodes. Mohs' surgery is probably useful. ELND and adjuvant radiation should be considered (184). Nodal disease is best approached with surgical excision of the primary site and therapeutic lymph node dissection. Chemotherapy is not effective.

Primary cutaneous adenoid cystic carcinoma (PCACC) is a rare tumor with eccrine/apocrine origin (185). It affects both men and women at a mean age of 59 years (range, 14-90 years). The most common location is the scalp, followed by the trunk and extremities. Tumors resemble furuncles or larger erythematous nodules. Metastases occur in 11% of cases, mostly to the lungs. On histological examination, PCACC is indistinguishable from adenoid cystic carcinoma of salivary glands. There are uniform basaloid cells with oval nuclei, solitary nucleoli, and rare mitotic figures. Two patterns exist: a cribiform pattern with pseudolumina resembling Swiss cheese and a tubular pattern with multiple ductlike structures. The tumor is deep dermal and has no connection to the epidermis. There is frequent perineural involvement. IHC stains are positive for EMA, CEA, and CK. Surgical excision results in a 64% recurrence rate. Larger size and perineural involvement are risk factors. Mohs' micrographic surgery has been successfully attempted in at least two cases but the follow-up has been too short for definitive results (186). One case treated with radiation recurred after 15 months. Recurrent tumors are best approached with Mohs' surgery. It is impossible to make recommendations regarding metastatic disease due to the scarcity of reported cases.

Malignant cylindroma may arise de novo or from pre-existing benign cylin-dromas. Risk factors for malignant transformation of cylindroma include chronic irritation and trauma, incomplete excision, and ionizing radiation. Approximately 90% of cases involve the scalp and women are more commonly affected. Malignant cylindroma affects the elderly (average age, 72) and latency from onset of benign tumor to malignant transformation is 27 years (187). Cylindromas are red, firm nodules of various sizes. Malignant transformation is manifested by rapid growth or ulceration. It is more likely in multiple tumors (64%) than in single neoplasms (36%). Regional metastases occur in 44% of cases. Distant metastases are possible to liver, lungs, or bone. Histopathological examination shows multiple irregular islands of uniform cells surrounded by a hyaline sheath. There are small cells with dark nuclei at the periphery and large, pale cells at the center. IHC stains are positive for CEA, EMA, and CK. Surgical excision results in a 36% recurrence rate. Mohs' surgery may be useful. Radiation is not recommended. Regional disease is approached with therapeutic lymph node dissection. Distant metastatic disease is incurable (188).

Paget's disease of the nipple originates in luminal lactiferous ducts of breast tissue. It affects women in the fifth decade of life (a decade older than most breast cancer patients) and is frequently associated with an underlying intraductal carcinoma. Paget's disease presents clinically as an erythematous scaly patch that, in con- >3 trast to benign eczema, is indurated and well-demarcated (189). Mammography | shows changes in only 50-70% of cases. On histological examination there is a page- o toid distribution of large, pale, round cells in all layers of the epidermis. IHC staining § is positive for CEA, EMA, and CK. Mastectomy is the treatment of choice. @

Approximately 50% of patients have no associated intraductal carcinoma, and their survival is 100%. For those with underlying carcinoma, survival is 43% at 5 years. There is limited experience with conservative surgery in combination with radiotherapy (190). If nodes are positive, survival drops to 10% even after therapeutic lymph node dissection.

Extramammary Paget's disease (EMPD) differentiates into both eccrine and apocrine elements. The tumor presents as an erythematous scaly patch of variable size and indistinct border (Fig. 31). It resembles tinea, psoriasis, eczema, Bowen's disease, or superficial BCC. EMPD is usually located on the anogenital area, axillae head, or neck. It is more common in Whites and women during the sixth to ninth decades of life. Approximately 24% of patients have an underlying adnexal carcinoma and 12% of cases are associated with an internal malignancy of the gastrointestinal (GI) or genitourinary tract (191). Histopathological examination shows large pale epithelial cells in what is termed a buckshot distribution (Fig. 32). Some nests show glandular array. Dermal invasion signals the presence of adnexal carcinoma. IHC stains are positive for CEA, EMA, and GCDFP-15 (apocrine glands). EMPD is negative for S-100, HMB-45 (MM), or CK (SCC). Surgical excision or Mohs' surgery is the treatment of choice (192). IHC are useful to define surgical margins. Topical 5-FU is used preoperatively to delineate subclinical extension, and postoperatively to detect recurrences (193). Therapeutic lymph node dissection is indicated for nodal disease. Radical vulvectomy with bilateral groin lymphadenect-omy is recommended for invasive cases. Mohs' surgery is the treatment of choice for

Figure 31 Long-standing erythematous scaly patch on the pubic area that was repeatedly treated as tinea and eczema without response. A diagnostic biopsy specimen showed extramammary Paget's disease. A short course of topical 5-FU was used to delineate subclinical extension prior to treatment with Mohs' surgery.

Figure 31 Long-standing erythematous scaly patch on the pubic area that was repeatedly treated as tinea and eczema without response. A diagnostic biopsy specimen showed extramammary Paget's disease. A short course of topical 5-FU was used to delineate subclinical extension prior to treatment with Mohs' surgery.

Extramammary Paget Disease Post Mohs

Figure 32 Histopathological examination in Paget's disease shows characteristic proliferation of large pale cells in a buckshot distribution. Some glandular-like nests are evident at the level of the hair follicle. Such pagetoid proliferation is seen also in malignant melanoma and squamous cell carcinoma, and differentiation is established with the help of immunohisto-chemical stains.

Figure 32 Histopathological examination in Paget's disease shows characteristic proliferation of large pale cells in a buckshot distribution. Some glandular-like nests are evident at the level of the hair follicle. Such pagetoid proliferation is seen also in malignant melanoma and squamous cell carcinoma, and differentiation is established with the help of immunohisto-chemical stains.

recurrent tumors (194). Radiation therapy and chemotherapy are not curative but may be useful as palliation in advanced cases. The initial work-up should include physical and rectal examination, sigmoidoscopy, and cystoscopy. For women, mammography and colposcopy are also indicated. Mortality is 18% but increases to 46% if associated with adnexal or visceral neoplasia.

Malignant hidradenoma papilliferum (MHP) arises from pre-existing benign hidradenoma papilliferum (HP). There are no other known risk factors. MHP and HP present clinically as nonspecific dermal nodules with normal overlying skin. The tumor affects women more than men, and Whites more than other races. The most common location is the anogenital area. Although HP affects prepubertal patients, MHP is usually seen in middle-aged women (195). Histopathological examination shows an encapsulated dermal tumor without connection to the epidermis. There are tubular and cystic structures with papillary projections. Active decapitation secretion is a characteristic feature common to apocrine neoplasms. IHC stains are positive for CK, CEA, S-100, and GCDFP-15. Surgical excision with 2 t cm margins is the treatment of choice (196). Mohs' surgery is a valid alternative. ^

Apocrine carcinoma (AC) is a rare tumor that accounts for 0.005% of surgical >3

specimens. The tumor usually affects areas rich in apocrine glands such as the axilla, anogenital area, external auditory canal (EAC), Moll's glands in the eyelid, and mammary glands. Peak incidence is during the fifth to sixth decade without gender predominance (197). The only risk factor may be ionizing radiation. AC presents non- @

characteristically as a firm or cystic, nontender dermal nodule of variable size. Lesions are single, mobile, and red, blue, or skin-colored. On histological examination, AC shows glandular nests and cords of polygonal eosinophilic cells forming lumina (ductopapillary variety). Signs of malignancy include atypia, nuclear pleomorphism, necrosis, vascular or perineural invasion, and poor delimitation. IHC staining is positive for CEA, EMA, CK, and GCDFP-15. Wide surgical excision is the treatment of choice but 80% recurrence rates have been reported. Metastases occur in 30%, mostly to lymph nodes, but also to lungs, liver, and bone. Mohs' surgery may improve cure rates (198). It is currently indicated for cosmetic areas, tissue preservation, and recurrent tumors. Therapeutic lymph node dissection is performed for nodal disease. Consider sentinel node biopsy (see section on malignant melanoma). Metastatic disease is treated with chemotherapy. Radiation therapy is ineffective.

How To Prevent Skin Cancer

How To Prevent Skin Cancer

Complete Guide to Preventing Skin Cancer. We all know enough to fear the name, just as we do the words tumor and malignant. But apart from that, most of us know very little at all about cancer, especially skin cancer in itself. If I were to ask you to tell me about skin cancer right now, what would you say? Apart from the fact that its a cancer on the skin, that is.

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