Angthong Chayanin, Kintarak Jutatip, Kanitnate Supakit, Angthong Wirana
Department of Orthopaedic Surgery, Faculty of Medicine, Thammasat University Hospital, Thammasat University, Pathumthani, Thailand.
J Med Assoc Thai. 2012 Jan;95 Suppl 1:S183-9.
Eccrine poroma is a benign appendage tumor showing either eccrine or apocrine differentiation. However malignant transformation of this tumor is very rare. The present report demonstrated a case of the eccrine poroma with malignant transformation and its rarity in terms of its high degree of recurrences and its aggressiveness with bony invasion.
A 67-year old female had a mass on plantar surface of 4th-5th intermetatarsal area of her left foot for 10 years with three recurrent episodes following excisions at local hospital with no pathological report. She was referred to our institute. A recurrent tumor was removed again with pathological findings as eccrine poroma with incomplete excision; however; the patient had a failure to follow-up. Four years later; she was back in our center again with 5th episode of recurrent tumor which was marginally excised with pathological findings revealing a malignant transformation of eccrine poroma with close resected margins. Unfortunately, the patient failed to follow-up again. Eventually, four years later she returned to our institute with 6th recurrent episode of tumor. Incisional biopsy was performed with pathological findings as appendage tumor with eccrine differentiation. Wide resection including removal of 5th metatarsal head-and-neck was performed due to aggressive behaviors of this tumor; particularly; history of malignant findings and multiple recurrences, significantly bony invasion. Final pathologicalfindings were malignant eccrine poroma with close resected margin. There were no metastases in evidence from all investigations. Local irradiation with the aim of eradication of microscopically residual tumor was initiated.
Malignant transformation is a rare occurrence of eccrine poroma. It should be initially included in differential diagnoses, especially in a patient with long standing foot lesion or history of recurrent masses. Wide excision is recommended as basis treatment, especially in a patient with high likelihood of recurrences or positive malignant transformation.
小汗腺汗孔瘤是一种显示小汗腺或大汗腺分化的良性附属器肿瘤。然而，这种肿瘤的恶性转化非常罕见。本报告展示了一例发生恶性转化的小汗腺汗孔瘤病例，其高度复发以及侵袭骨质的侵袭性方面都很罕见。
一名67岁女性，左足第4 - 5跖骨间区域足底有一肿物10年，在当地医院切除后复发3次，未获得病理报告。她被转诊至我院。再次切除复发性肿瘤，病理结果为小汗腺汗孔瘤，切除不完全；然而，患者未进行随访。4年后，她再次回到我院，出现第5次复发性肿瘤，行边缘切除，病理结果显示小汗腺汗孔瘤恶性转化，切缘紧邻。不幸的是，患者再次未进行随访。最终，4年后她因肿瘤第6次复发回到我院。进行了切开活检，病理结果为具有小汗腺分化的附属器肿瘤。由于该肿瘤具有侵袭性行为，特别是有恶性发现史和多次复发，明显侵袭骨质，故进行了包括切除第5跖骨头颈部的广泛切除。最终病理结果为切缘紧邻的恶性小汗腺汗孔瘤。所有检查均未发现转移证据。开始进行局部放疗以根除显微镜下残留的肿瘤。
恶性转化是小汗腺汗孔瘤的罕见情况。应首先将其纳入鉴别诊断，尤其是对于有长期足部病变或复发性肿物病史的患者。建议广泛切除作为基本治疗方法，特别是对于复发可能性高或有恶性转化阳性的患者。
