[Primary eccrine porocarcinoma: a clinicopathological study of 50 cases].
BACKGROUND
Eccrine porocarcinoma is a rare cutaneous tumor arising from the intra-epidermal portion of eccrine sweat glands, the acrosyringium. Histoprognostic studies in large series are rare. Herein, we report a retrospective study of 50 cases.


METHODS
Fifty cases of porocarcinoma were retrieved from a histopathological register. Each histopathological sample was evaluated for the following criteria: presence or absence of dermal invasion, pattern of the infiltrative component (pushing or infiltrative), tumor thickness, lymphovascular emboli, perineural invasion and mitotic index. Clinical data and outcome were also retrieved for each patient.


RESULTS
Mean patient age was 77 years (range: 43-99 years). The mean duration of progression prior to diagnosis was 4 years and 5 months. The 2 most common skin locations were the head (38%) and lower limbs (20%). The lesions showed no specific distinctive clinical features. Six cases were in situ, and 44 were invasive (23 with limited infiltration and 20 with scattered infiltration). Mean tumor thickness was 4.37 mm (range: 0.5 to 20 mm). Neighboring or remote epidermal involvement was noted in 7 cases. Lymphovascular emboli were observed in 3 cases. No cases of neurotropism were observed. The average mitotic index was 6.5 mitoses/high power (×400) field. A mean follow-up of 24.3 months was available for 48 patients. Local recurrence was noted in 5 patients, 4 of whom died from visceral metastases. These 5 cases showed no distinctive clinical features, a scattered pattern of the invasive component, cuticular cells, significant tumor thickness (mean 12.8 mm, range 9-20 mm), and an elevated mitotic index. Two histopathological criteria were significantly associated with a metastatic outcome: scattered pattern of the dermal invasive component (P=0.04) and significant tumor thickness, above 10mm (P<0.01).


CONCLUSIONS
Porocarcinoma is a tumor without any particular clinical criteria to distinguish it from squamous cell carcinoma. The architecture of the invasive component and tumor thickness constitute 2 important histoprognostic criteria.
Service de dermatologie, 179, boulevard Maréchal-Juin, 26000 Valence, France. Electronic address: skowron.francois@wanadoo.fr.
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Skowron
Service de dermatologie, centre hospitalier Lyon-Sud (Pierre-Bénite), université Lyon 1, 165, chemin du Grand-Revoyet, 69495 Pierre-Bénite cedex, France.
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Poulhalon
Service d'anatomie pathologique, centre hospitalier Lyon-Sud (Pierre-Bénite), 165, chemin du Grand-Revoyet, 69495 Pierre-Bénite cedex, France.
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Balme
Département d'information médicale, hospices Civils de Lyon, avenue Lacassagne, 69424 Lyon cedex 03, France.
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Touzet
Service de dermatologie, centre hospitalier Lyon-Sud (Pierre-Bénite), université Lyon 1, 165, chemin du Grand-Revoyet, 69495 Pierre-Bénite cedex, France.
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Thomas
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D057090:Eccrine Porocarcinoma / Q000175:diagnosis / Q000401:mortality / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D006257:Head / Q000473:pathology; D006801:Humans; D035002:Lower Extremity / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis / Q000401:mortality / Q000473:pathology*; D009367:Neoplasm Staging; D012189:Retrospective Studies; D016019:Survival Analysis; D013544:Sweat Gland Neoplasms / Q000175:diagnosis / Q000401:mortality / Q000473:pathology*; D060726:Torso / Q000473:pathology; D034941:Upper Extremity / Q000473:pathology
Adnexal skin tumor; Eccrine porocarcinoma; Facteurs histopronostiques; Histopathology; Non-melanoma skin cancer; Porocarcinome eccrine; Tumeur annexielle