Clinic Pathological Study of an Eccrine Spiradenoma

Eccrine spiradenoma (ES) is an exceedingly rare sweat-gland tumor, it usually presents as a solitary lesion and painful nodule. ES is a kind of neoplasm with distinct histological characteristics and nonspecific clinical manifestations. Most ES cases have a benign course; however, malignant transformation would occur after a long period of latency. The diagnosis mostly depends on the clinic symptom, histological features and immunohistochemistry. Here, we report a case of ES and literature review. The aim of this study is to understand clinic and histological features for ES.


Introduction
Eccrine spiradenoma (ES) is a rare, benign tumor of eccrine gland and has characteristic clinical and histomorphological features. ES was first reported by Kersting and Helwig in 1956 [1]. It may occur in patients of any age, although they are most frequently seen in the 2 nd and 4 th decades of life as a painful solitary well-circumscribed dermal nodule with pink or blue hue. They do not have sex predominance [2]. The common sited for ES are head, neck, trunk and extremities. There are only a few reports describing the clinic and pathological features of ES. Here, one case of ES of upper jaw was reported at Department of Pathology in Chongqing Medical University and discusses the clinical and pathological features of ES with combined of review of cases in the literatures.

1) MATERIALS: One case of ES was diagnosed at Department of Pathology in
Chongqing Medical University.
2) METHODS: The formalin-fixed, paraffin-embedded tissue was sectioned at 5 um thickness for standard immunohistochemical staining. Slides in absolute ethanol, 2 min in 95% ethanol, 2 min in 80% ethanol, and 5 min in distilled water, then rehydrated into distilled H 2 O 2 through graded ethanol. Antigen retrieval was used to enhance CKpan, EMA, P63, P40, S100, CK20, CK5/6, CEA, GCDFP-15 and KI67 immunohistochemic by high press in citrate buffer (PH 6.0) for 3 min. Then the sections were washed and incubated those with 1 hour at room temperature. Slides were washed in phosphate-buffered saline, and then incubated with secondary antibody for 20 min at room temperature. After washed, slides were stained with DAB until desired stain intensity developed and mounted before observation by light microscopy. presented in this case [ Figure 4]. Negative expression of CK20 was observed in this case.

1) Clinical Findings
3) Discussion: ES are rare benign tumors originating from the sweat glands, which are present throughout the body, but the common sites are head, neck, trunk and extremities. Most of lesions are single, occasionally are multiple [3]. They can range in size from 0.3 -10.0 cm and associated with pain and tenderness [4]. They usually occur in the 2 nd-4 th decade of life. They do not have sex predominance [5]. The pathogenesis of ES is unknown. Some scholars believed that the pain due to ES is related to the presence of small unmyelinated axons in the context of the connective tissue around the tumor, or to the expansion of the cysts. Multiple ES has a family history and is autosomal dominant inheritance. 4) Histologically: There are single or multiple nodules which are wrapped by fibrous tissue. Tumor situated in the reticular dermis, will be extending into the   reported in 1972 by Dabska [6]. Malignant degeneration of ES usually appears in long-standing tumors which are clinically revealed by a rapidly enlarging mass.
All of the malignant lesions reported in the literatures had evolved from benign lesions. A complete wide excision is the best treatment of choice for single benign Eccrine Spiradenoma. For patient with multiple lesions, there was a report of radiotherapy and laser treatment [7].
In conclusion, ES is a benign tumor which rarely shows malignant transformation. So, early and correct diagnosis of ES is critical, especially occurrence at rare sites. The accurate diagnosis of ES must correlate clinical and histopathological examinations. For the patients with skin lesion increased rapidly, color changed, and pain increased, which were suspected of malignant transformation, should be undergoing surgical resection as soon as possible.

Conflicts of Interest
The authors declare no conflicts of interest regarding the publication of this paper.