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Leiomyosarcoma of scrotum—case report and review of literature
CASE REPORT
LEIOMYOSARCOMA OF SCROTUM—CASE REPORT AND REVIEW OF LITERATURE T. JOHN, D. PORTENIER, B. AUSTER, D. MEHREGAN, A. DRELICHMAN,
AND
A. TELMOS
ABSTRACT Leiomyosarcoma of the scrotum is a rare tumor. Cutaneous and subcutaneous leiomyosarcomas constitute the two subtypes. We report a case of cutaneous leiomyosarcoma of the scrotum in a 73-year-old man. Cutaneous leiomyosarcoma arises from the smooth muscle of the dartos or arrectores pilorum. It is often mistaken for a benign lesion. We describe the clinical and pathologic features and review the published reports of this uncommon malignancy. It is best treated by wide local excision. Inguinal lymph node dissection is not advocated, unless a high degree of suspicion is present for lymph node metastasis. Long-term follow-up is essential, because of the risk of delayed local recurrence and distant metastasis. UROLOGY 67: 424.e13–424.e15, 2006. © 2006 Elsevier Inc.
S
crotal leiomyosarcomas not arising from the spermatic cord, epididymis, or testes are rare. They usually occur in middle-aged and elderly men. Local irradiation is a possible etiologic factor.1 It presents as a painless, slow-growing, cutaneous lesion and often resembles a cyst. They are often mistaken for a benign condition, with the true diagnosis revealed only on pathologic examination. CASE REPORT A 73-year-old man presented with a nodular lesion on the scrotum that he had noticed 4 months previously. It was pruritic. His surgical history was significant for amelanotic melanoma on his nose, which had been excised. On local examination, a 6-mm inflamed cystic nodule was noted on the scrotum, near the central raphe. No inguinal lymphadenopathy was present. The lesion was excised as an office procedure, under local anesthesia. Pathologic examination revealed a low-grade leiomyosarcoma, extending close to the resection margin, but with a narrow rim of normal dermis. The epidermis was slightly acanthotic. The nodule From Providence Hospital, Southfield, Michigan; Oakland Aesthetic Dermatology, Farmington Hills, Michigan; and Pinkus Dermatopathology Laboratory, PC, Monroe, Michigan Address for correspondence: T. John, M.D., Department of Surgery, Providence Hospital, 16001 West Nine Mile Road, Southfield, MI 48075. E-mail: [email protected] Submitted: April 28, 2005, accepted (with revisions): September 16, 2005 © 2006 ELSEVIER INC. ALL RIGHTS RESERVED
was well-defined (Fig. 1) and consisted of a proliferation of cells with cigar-shaped nuclei and eosinophilic cytoplasm. The proliferation showed cellular pleomorphism with bizarre and giant tumor cells (Fig. 2). The mitotic count was low, suggestive of a low-grade leiomyosarcoma. The cells stained positive for vimentin, actin, and desmin on immunohistochemistry and were negative for S100. Desmin is an intermediate filament and is found in cells of muscular origin. Computed tomography of the thorax, abdomen, and pelvis showed no evidence of metastatic disease. Wide excision of the leiomyosarcoma site on the scrotum was done. An elliptical incision was made, circumscribing the previous excision site en bloc, with 2-cm margin, down to the dartos muscle. Pathologic examination did not reveal the presence of any residual malignancy. The patient was alive, with no evidence of local recurrence or metastatic disease, 9 months after the initial diagnosis. COMMENT Leiomyosarcomas arise from cells of mesenchymal origin. In the skin, smooth muscle is seen in the walls of blood vessels and along hair follicles (arrectores pilorum). In addition, the specialized muscle of the genital skin, the dartos, is seen in the scrotum. Leiomyosarcomas of the scrotal wall usually arise from the dartos muscle, but they cannot be differentiated from other leiomyosarcomas of the skin by histologic examination alone.2 0090-4295/06/$32.00 doi:10.1016/j.urology.2005.09.022 424.e13
FIGURE 1. Relatively well-defined dermal nodule.
Leiomyosarcomas are divided into two subtypes depending on the location. Cutaneous leiomyosarcomas arise from the arrectores pilar muscle of the hair follicle or dartos muscle of the genital skin. They are present in the dermis and may extend into the subcutaneous fat. Subcutaneous leiomyosarcomas arise from the muscle lining of arterioles and veins in the subcutaneous tissue. The tumor is composed of highly cellular fascicles of spindle-shaped cells. The lesion may be relatively well-defined or poorly circumscribed. The fascicles are arranged in irregular, interlacing bundles, often intersecting at right angles. The cells have nuclei that are elongated and blunt ended giving a “cigar” appearance. The degree of differentiation may vary within a single tumor. In some well-differentiated areas, the cells resemble the typical smooth muscle cells of leiomyomas. Other areas may be poorly differentiated, with extensive cellular atypia and prominent nuclei and nucleoli. Mitotic figures are seen throughout the lesion. If the lesion is poorly differentiated, special stains, such as Masson’s trichrome or immunohistochemical studies, including actin and desmin, can differentiate the muscular origin of the lesion. Mitosis is used to differentiate leiomyosarcoma from benign leiomyoma. At least two mitosis per 10 high power fields should be seen.3 The lymphatic drainage is mainly to the inguinal and iliac nodes. Secondary tumors in the lymph nodes are rare. Recurrence is mainly local. Inguinal lymph node dissection is not advocated, unless a high degree of suspicion for lymph node metastasis is present. 424.e14
FIGURE 2. (A,B) Cell proliferation of atypical bizarre giant tumor cells with eosinophilic cytoplasm and cigarshaped nuclei.
Long-term follow-up is needed, because late recurrences can develop. Distant metastases have been reported to the lungs4 and soft tissues of the neck.5 The prognosis differs depending on the subtype. Some investigators1 found a greater rate of local recurrence for subcutaneous tumors, and others5 have found the rates to be similar. However, it is generally accepted that distant metastasis is much greater with the subcutaneous type. The prognosis is generally good in the absence of local recurrence. A positive margin at the first excision dramatically increases the risk of local recurrence. It is therefore important that even the most benign-looking scrotal lesion be excised completely and tissue sent for pathologic examination. The importance of long-term follow-up needs to be emphasized, because local recurrence and distant metastasis can occur years after the initial excision. UROLOGY 67 (2), 2006
REFERENCES 1. Dalton DP, Rushovich AM, Victor TA, et al: Leiomyosarcoma of the scrotum in a man who had received scrotal irradiation as a child. J Urol 139: 136 –138, 1988. 2. Flotte TJ, Bell DA, Sidhu GS, et al: Leiomyosarcoma of the dartos muscle. J Cutan Pathol 8: 69 –74, 1981.
UROLOGY 67 (2), 2006
3. Moon TD, Sarma DP, and Rodriguez FH Jr: Leiomyosarcoma of the scrotum. J Am Acad Dermatol 20: 290 –292, 1989. 4. Johnson H Jr: Leiomyosarcoma of scrotum. Urology 29: 436 – 438, 1987. 5. Washecka RM, Sidhu G, and Surya B: Leiomyosarcoma of scrotum. Urology 34: 144 –146, 1989.
424.e15
LEIOMYOSARCOMA OF SCROTUM—CASE REPORT AND REVIEW OF LITERATURE T. JOHN, D. PORTENIER, B. AUSTER, D. MEHREGAN, A. DRELICHMAN,
AND
A. TELMOS
ABSTRACT Leiomyosarcoma of the scrotum is a rare tumor. Cutaneous and subcutaneous leiomyosarcomas constitute the two subtypes. We report a case of cutaneous leiomyosarcoma of the scrotum in a 73-year-old man. Cutaneous leiomyosarcoma arises from the smooth muscle of the dartos or arrectores pilorum. It is often mistaken for a benign lesion. We describe the clinical and pathologic features and review the published reports of this uncommon malignancy. It is best treated by wide local excision. Inguinal lymph node dissection is not advocated, unless a high degree of suspicion is present for lymph node metastasis. Long-term follow-up is essential, because of the risk of delayed local recurrence and distant metastasis. UROLOGY 67: 424.e13–424.e15, 2006. © 2006 Elsevier Inc.
S
crotal leiomyosarcomas not arising from the spermatic cord, epididymis, or testes are rare. They usually occur in middle-aged and elderly men. Local irradiation is a possible etiologic factor.1 It presents as a painless, slow-growing, cutaneous lesion and often resembles a cyst. They are often mistaken for a benign condition, with the true diagnosis revealed only on pathologic examination. CASE REPORT A 73-year-old man presented with a nodular lesion on the scrotum that he had noticed 4 months previously. It was pruritic. His surgical history was significant for amelanotic melanoma on his nose, which had been excised. On local examination, a 6-mm inflamed cystic nodule was noted on the scrotum, near the central raphe. No inguinal lymphadenopathy was present. The lesion was excised as an office procedure, under local anesthesia. Pathologic examination revealed a low-grade leiomyosarcoma, extending close to the resection margin, but with a narrow rim of normal dermis. The epidermis was slightly acanthotic. The nodule From Providence Hospital, Southfield, Michigan; Oakland Aesthetic Dermatology, Farmington Hills, Michigan; and Pinkus Dermatopathology Laboratory, PC, Monroe, Michigan Address for correspondence: T. John, M.D., Department of Surgery, Providence Hospital, 16001 West Nine Mile Road, Southfield, MI 48075. E-mail: [email protected] Submitted: April 28, 2005, accepted (with revisions): September 16, 2005 © 2006 ELSEVIER INC. ALL RIGHTS RESERVED
was well-defined (Fig. 1) and consisted of a proliferation of cells with cigar-shaped nuclei and eosinophilic cytoplasm. The proliferation showed cellular pleomorphism with bizarre and giant tumor cells (Fig. 2). The mitotic count was low, suggestive of a low-grade leiomyosarcoma. The cells stained positive for vimentin, actin, and desmin on immunohistochemistry and were negative for S100. Desmin is an intermediate filament and is found in cells of muscular origin. Computed tomography of the thorax, abdomen, and pelvis showed no evidence of metastatic disease. Wide excision of the leiomyosarcoma site on the scrotum was done. An elliptical incision was made, circumscribing the previous excision site en bloc, with 2-cm margin, down to the dartos muscle. Pathologic examination did not reveal the presence of any residual malignancy. The patient was alive, with no evidence of local recurrence or metastatic disease, 9 months after the initial diagnosis. COMMENT Leiomyosarcomas arise from cells of mesenchymal origin. In the skin, smooth muscle is seen in the walls of blood vessels and along hair follicles (arrectores pilorum). In addition, the specialized muscle of the genital skin, the dartos, is seen in the scrotum. Leiomyosarcomas of the scrotal wall usually arise from the dartos muscle, but they cannot be differentiated from other leiomyosarcomas of the skin by histologic examination alone.2 0090-4295/06/$32.00 doi:10.1016/j.urology.2005.09.022 424.e13
FIGURE 1. Relatively well-defined dermal nodule.
Leiomyosarcomas are divided into two subtypes depending on the location. Cutaneous leiomyosarcomas arise from the arrectores pilar muscle of the hair follicle or dartos muscle of the genital skin. They are present in the dermis and may extend into the subcutaneous fat. Subcutaneous leiomyosarcomas arise from the muscle lining of arterioles and veins in the subcutaneous tissue. The tumor is composed of highly cellular fascicles of spindle-shaped cells. The lesion may be relatively well-defined or poorly circumscribed. The fascicles are arranged in irregular, interlacing bundles, often intersecting at right angles. The cells have nuclei that are elongated and blunt ended giving a “cigar” appearance. The degree of differentiation may vary within a single tumor. In some well-differentiated areas, the cells resemble the typical smooth muscle cells of leiomyomas. Other areas may be poorly differentiated, with extensive cellular atypia and prominent nuclei and nucleoli. Mitotic figures are seen throughout the lesion. If the lesion is poorly differentiated, special stains, such as Masson’s trichrome or immunohistochemical studies, including actin and desmin, can differentiate the muscular origin of the lesion. Mitosis is used to differentiate leiomyosarcoma from benign leiomyoma. At least two mitosis per 10 high power fields should be seen.3 The lymphatic drainage is mainly to the inguinal and iliac nodes. Secondary tumors in the lymph nodes are rare. Recurrence is mainly local. Inguinal lymph node dissection is not advocated, unless a high degree of suspicion for lymph node metastasis is present. 424.e14
FIGURE 2. (A,B) Cell proliferation of atypical bizarre giant tumor cells with eosinophilic cytoplasm and cigarshaped nuclei.
Long-term follow-up is needed, because late recurrences can develop. Distant metastases have been reported to the lungs4 and soft tissues of the neck.5 The prognosis differs depending on the subtype. Some investigators1 found a greater rate of local recurrence for subcutaneous tumors, and others5 have found the rates to be similar. However, it is generally accepted that distant metastasis is much greater with the subcutaneous type. The prognosis is generally good in the absence of local recurrence. A positive margin at the first excision dramatically increases the risk of local recurrence. It is therefore important that even the most benign-looking scrotal lesion be excised completely and tissue sent for pathologic examination. The importance of long-term follow-up needs to be emphasized, because local recurrence and distant metastasis can occur years after the initial excision. UROLOGY 67 (2), 2006
REFERENCES 1. Dalton DP, Rushovich AM, Victor TA, et al: Leiomyosarcoma of the scrotum in a man who had received scrotal irradiation as a child. J Urol 139: 136 –138, 1988. 2. Flotte TJ, Bell DA, Sidhu GS, et al: Leiomyosarcoma of the dartos muscle. J Cutan Pathol 8: 69 –74, 1981.
UROLOGY 67 (2), 2006
3. Moon TD, Sarma DP, and Rodriguez FH Jr: Leiomyosarcoma of the scrotum. J Am Acad Dermatol 20: 290 –292, 1989. 4. Johnson H Jr: Leiomyosarcoma of scrotum. Urology 29: 436 – 438, 1987. 5. Washecka RM, Sidhu G, and Surya B: Leiomyosarcoma of scrotum. Urology 34: 144 –146, 1989.
424.e15