Palisaded and verocay body prominent leiomyoma of deep soft tissue

Leiomyoma of deep soft tissue is a very rare tumor, which is sometimes confused with leiomyosarcoma, histopathologically. We describe a case of palisaded and Verocay-body prominent leiomyoma of deep soft tissue. The lesion was characterized by areas of nuclear palisading with Verocay-body like formation in addition to the features of leiomyoma.     

Two cases of male nipple leiomyoma: idiopathic leiomyoma and gynecomastia-associated leiomyoma

We describe 2 cases of male nipple leiomyoma. A 70-year-old man had a painful subcutaneous tumor on his left nipple of 6 months duration. Histopathology disclosed dermal spindle cells with oval-shaped nuclei forming interlacing bundles with irregular pattern. Glandular elements were absent. The spindle cells were positive to α-smooth muscle actin, desmin, and vimentin. Estrogen receptor (ER) and progesterone receptor (PrR) were negative. We diagnosed this case as male leiomyoma of the nipple. Another patient was a 61-year-old man with gynecomastia induced by spironolactone of 6 months duration. He also had a painful nodule on his left nipple and histopathology disclosed spindle-shaped tumor cells as in the previous patient. The tumor was accompanied by glandular elements in the deep dermis and subcutaneous tissue, which showed apocrine secretion and were positive for α-smooth muscle actin, ER, and PrR. These glandular elements were interpreted as mammary gland. But ER and PrR stain did not show positive results for leiomyoma in the upper dermis. To the best of our knowledge, this is the first report of male idiopathic and gynecomastia-induced leiomyoma with ER and PrR staining.     

Desmoplastic fibroblastoma: a case presenting as a protruding nodule in the dermis

Desmoplastic fibroblastoma is a rare, benign, soft tissue tumor. We describe a case of superficial desmoplastic fibroblastoma presenting as a protruding nodule. A 41-year-old woman presented with a painless, firm, elevated nodule with ulceration on her left thigh. Histological examination from total excision showed a well-circumscribed tumor in the dermis, which comprised of spindle, oval and stellate cells arranged in a haphazard fashion, accompanied by abundant collagenous stroma and inconspicuous vasculature. Immunohistochemically, the tumor cells were positive for vimentin, and focally positive for alpha-smooth muscle actin and muscle-specific actin, but negative for CD34, S-100 protein, desmin and beta-catenin. We diagnosed this case as desmoplastic fibroblastoma arising in the dermis and superficial subcutaneous tissue.     

Solitary Cutaneous Leiomyoma in an Infant

Abstract:   This report describes a case of leiomyoma of the ankle occurring at an unusual age. A 5-month-old girl presented with an asymptomatic nodule on her left ankle.     

Differential expression of smooth muscle myosin, smooth muscle actin, h-caldesmon, and calponin in the diagnosis of myofibroblastic and smooth muscle lesions of skin and soft tissue

The diagnosis of low-grade and pseudosarcomatous spindle cell lesions of skin and soft tissue can sometimes be problematic; in particular, distinction between fibroblastic, myofibroblastic, and smooth muscle proliferations can occasionally pose difficulties on routine histologic examination. We have applied a panel of immunohistochemical markers to a series of spindle cell lesions of skin and soft tissue to assess the utility of the differential expression of smooth muscle and myofibroblastic-associated markers. Twenty-eight cases of nodular fasciitis, 42 cases of fibromatosis, and 3 cases of myofibroblastic sarcoma were stained with antibodies against smooth muscle actin (SMA), smooth muscle myosin (SMMS), calponin, and high-molecular weight caldesmon (h-caldesmon). For comparison, 12 cases of cutaneous leiomyoma and 8 cases of leiomyosarcomas involving superficial soft tissues and fascia were studied with the same panel of antibodies. Thirty-eight of 42 cases of fibromatosis were positive for SMA, 42/42 cases were positive for calponin, 39/42 cases were negative for SMMS, and all cases were negative for h-caldesmon. All cases of nodular fasciitis were positive for SMA and calponin, and all were negative for h-caldesmon and SMMS. All cases of myofibroblastic sarcoma were positive for SMA and 2/3 cases for calponin, and were negative for SMMS and h-caldesmon. All cases of cutaneous leiomyoma and leiomyosarcoma were positive for all 4 markers tested. Our results demonstrate a remarkably consistent pattern of reactivity of muscle and myofibroblastic-associated markers in lesions predominantly composed of myofibroblastic spindle cells, characterized by positive staining for SMA and calponin and absence of reactivity for SMMS and h-caldesmon. Application of this panel of stains may be of aid in the differential diagnosis of low-grade myofibroblastic lesions such as nodular fasciitis and fibromatosis from smooth muscle tumors of skin and soft tissue. This panel may additionally be of assistance in the diagnosis of myofibroblastic sarcoma.     

Primary cutaneous leiomysarcoma

Primary cutaneous leiomyosarcoma of the skin is a rare soft tissue neoplasm, accounting for about 2-3% of all superficial soft tissue sarcomas. It arises between the ages of 50 and 70 years, and shows a greater predilection for the lower extremities. Clinically, it presents with solitary, well-circumscribed nodule and, microscopically, consists of fascicles of spindle-shaped cells with "cigar-shaped" nuclei. Local recurrence is known in this tumor. We document a case of primary cutaneous leiomyosarcoma in a 77-year-old man and discuss the histological features and immunohistochemical profile of this uncommon neoplasm.     

Genital leiomyomas of the male nipple: two cases

BACKGROUND: Genital leiomyoma is a rare benign solitary skin tumor, not painful, developed from smooth muscle. Genital leiomyoma arising from the nipple is extremely rare, especially in males.CASES REPORT: A 47 year-old male had a 2 cm cutaneous plaque with nodules located on the right nipple. This plaque was circumscribed, erythematous, pruriginous and was not painful. The lesion had been noticed by the patient two years ago. A 37 year-old male showed a 1.5 cm cutaneous plaque located on the left nipple. The plaque was slightly erythematous, pruriginous, not painful and had been noticed by the patient 5 years earlier. Histology provided the diagnosis of genital leiomyoma in both cases. No surgical therapy was performed.DISCUSSION: Cutaneous leiomyomas are classified in 3 types regarding their origin: multiple or solitary piloleiomyoma, arising from arectores pilorum muscles, solitary genital leiomyoma, arising from the dartoic, vulvar, or mammillary muscles, and solitary angioleiomyoma, arising from the vein muscles. Clinically, genital leiomyoma is a 1 cm diameter solitary erythematous, firm nodule. According to many authors, genital leiomyoma is asymptomatic, but in the 2 patients, the lesions were pruriginous. Surgical excision is usually performed.     

A case of soft tissue mesenchymal chondrosarcoma metastatic to skin, clinically mimicking keratoacanthoma.

We report the first case of metastatic involvement of the skin by a soft tissue mesenchymal chondrosarcoma (MS). A 64-year-old man presented 15 months after resection of a 7.0 cm MS from his left forearm with a rapidly growing, erythematous nodule on the left side of the upper lip. The lesion was clinically interpreted as a keratoacanthoma. The histologic appearance was identical to that of the soft tissue MS; an immunohistochemical stain for CD99 was positive. Lung and bone metastases were subsequently documented. Our case expands the differential diagnosis of malignancies with cartilaginous differentiation that can involve the skin.     

Rhabdomyosarcoma presenting as a cutaneous nodule

Two patients with rhabdomyosarcoma presented clinically with dermal nodules on the face. The first patient was a 12-month-old girl with a 2 X 3-cm-diameter red nodule on her left cheek that had begun as a small red papule when she was 3 months old and had progressively increased in size. The second patient was a 19-year-old girl who presented with an enlarging mass on her right cheek that had begun as a pea-sized nodule three months previously. In both cases, biopsies revealed a rhabdomyosarcoma in the underlying soft tissue with extension into the overlying dermis. Rhabdomyosarcoma presenting as a dermal nodule is rare. It usually presents as an asymptomatic papule without distinctive clinical features and therefore may result in delayed diagnosis unless a biopsy is performed.     

Intramuscular lipoma within the temporal muscle

A 61-year-old male presented with a 6-month history of a subcutaneous nodule on the left forehead, which had gradually enlarged. He had suffered from headaches from 20 days before the first visit. His medical history included hepatitis C virus infection. He had had no history of trauma in this area. Clinical examination showed a subcutaneous soft nodule, 15 x 15 mm in size, which was adjacent to the left superficial temporal artery (Fig. 1). Though this artery revealed strong pulsation, the nodule had neither pulsation nor tenderness. His headache was localized in the left temporal area. He had no complaints of fever or weakness. Clinically, these features suggested a pseudoaneurysm of the superficial temporal artery. We operated on him under local anesthesia. An incision through the skin and subcutaneous fat exposed a nodule located within the temporal muscle. The fine branches of the superficial temporal artery reached out to the nodule through the muscle. After ligation of the branches, we resected the nodule surrounded by muscular tissue. Histopathology showed the proliferation of mature adipose cells embedded in muscular fibers. These cells had no nuclear pleomorphism or mitoses (Fig. 2). The tumor tissue contained partial fibrosis and some muscular fiber bundles scattered between the adipose cells (Fig. 3). Intramuscular lipoma within the temporal muscle was diagnosed. His headache was reduced after the operation, and he has had no recurrence of the tumor for 16 months. The relationship between the tumor and his headache was unknown.     

Primary cutaneous alveolar rhabdomyosarcoma in a pediatric patient

Rhabdomyosarcoma is the most common soft tissue tumor in childhood; however, it rarely affects only the skin. This case report describes a child with a painful nodule on her face. Histopathology and immunohistochemistry confirmed the diagnosis of rhabdomyosarcoma, and a multidisciplinary team then followed up the patient. Soft tissue tumors are responsible for 6% of all childhood tumors, and 53% of these are rhabdomyosarcomas, which may affect any part of the body. Presentation in the form of skin nodules is rare and represents a diagnostic challenge, since there are no clinical characteristics that differentiate this condition from other pathologies.     

Ossifying fibromyxoid tumor – A case report

Ossifying fibromyxoid tumor (OFMT) is a rare soft tissue tumor of uncertain histogenesis, occurring predominantly in deep soft tissues of the extremities. Typically, OFMT presents in adults on the extremities or trunk, as a deep soft tissue mass. Less appreciated is the fact that OFMT may also present as a mass in the superficial subcutis or dermis. We herein report a female who presented with an asymptomatic subcutaneous nodule on the left thigh for 3 years, and who was diagnosed as having typical ossifying fibromyxoid tumor, by unique histopathologic and immunohistochemical studies. Most reported cases have pursued a benign clinical course. However, recent literature emphasized the existence of morphologically atypical and clinically malignant cases of OFMTs. Pathologic criteria for malignancy have been proposed, and reclassification of these tumors as tumors of intermediate malignancy, raise our attention while coping with OFMT clinically.     

Melanoma malignum en cuirasse

We report on a 26-year-old male patient suffering from a rapidly progressing sclerodermiform induration and edema on his chest, neck, and face, which was more pronounced on the left side of his body. The disease had developed within two months and took a lethal course. Two months before the disease set on, the patient had removed a bluish nodule from his left axilla. Histopathologic analysis of the indurated skin showed massive infiltration of the fatty tissue by a malign, undifferentiated blastoma. Pathoanatomical investigation revealed a massive metastatic infiltration of the soft tissue in the thoracic area and the fatty tissue, as well as metastases developed in the lymph nodes.     

Benign fibrous histiocytoma with osteoclast-like giant cells in an infant

Abstract:  Benign fibrous histiocytoma is a common soft tissue tumor that usually occurs in adults and is relatively rare in childhood. This report describes a 7-month-old Caucasian boy with an enlarging firm congenital nodule on his occipital scalp. Histologic analysis revealed a benign fibrous histiocytoma with osteoclast-like giant cells. Benign fibrous histiocytoma with osteoclast-like giant cells is a rare histologic variant.     

Cutaneous leiomyosarcoma originating in a symplastic pilar leiomyoma: a rare occurrence and potential diagnostic pitfall

A case of cutaneous leiomyosarcoma originating in a symplastic pilar leiomyoma is described. The patient was a 60‐year‐old man who presented with a painless nodule on his chest. Thorough clinical examination did not reveal any evidence of tumor elsewhere. A punch biopsy was performed which showed a benign spindle cell neoplasm with focal cellular pleomorphism that had smooth muscle differentiation and was clearly originating from the arrector pili muscle, consistent with a cutaneous symplastic pilar leiomyoma. Immunohistochemical studies were performed and the tumor cells were strongly positive for smooth muscle actin (SMA) and desmin. Given the clinical information of a mass on the chest, clinical evaluation was recommended and a re‐excision was performed. Histologically, the re‐excision showed two distinct populations of cells. The upper portion of the tumor mirrored the initial biopsy; however, the base of the tumor showed hypercellular areas composed of spindle cells with marked pleomorphism and increased number of mitoses. The diagnosis of a cutaneous leiomyosarcoma originating in a symplastic pilar leiomyoma was given. This is the first report of this association of such occurrence reported in the literature. Fons ME, Bachhuber T, Plaza JA. Cutaneous leiomyosarcoma originating in a symplastic pilar leiomyoma: a rare occurrence and potential diagnostic pitfall.     

Leiomioma de la areola mamaria. Presentación de dos casos

—Cutaneous genital or dartoic leiomyomas are rare benign tumors originating in the smooth muscle fibers of the skin of the scrotum, vulva, nipple and areola. The latter are the less frequently observed.We report two cases of leiomyoma of the areola. Both presented as a solitary, small, nonulcerated nodule. Histopathological features shared similar characteristics: a non-encapsulated, ill-defined tumor in superficial and mid-dermis composed of spindle cells with elongated nuclei and eosinophilic cytoplasm, arranged in interdigitating fascicles. There were no atypia or mitoses. It was remarkable a reactive epidermal hyperplasia overlying the surface of the tumor, as is typically seen in the histiocytomas. Areolar leiomyoma is a benign lesion that is not known to undergo malignant transformation, although it may be confused clinically with carcinoma of the breast.     

A case of extensor digitorum brevis manus

The extensor digitorum brevis manus (EDBM), a relatively rare anomalous muscle on the dorsal hand, may be misdiagnosed as a ganglion, a synovial nodule or cyst, or a soft-tissue tumor. MRI scans can help to distinguish EDBM from tumors. EDBM should be included in the differential diagnosis of soft tissue masses on the dorsal aspect of the hand.     

EWSR1‐PBX3 gene fusion in cutaneous syncytial myoepithelioma

Cutaneous syncytial myoepithelioma (CSM) is a recently recognized, histopathological variant of myoepithelial (ME) tumors of the skin. It is characterized by a syncytial arrangement of spindled, ovoid, and/or epithelioid cells forming a well‐circumscribed, unencapsulated dermal nodule. There is a paucity of intervening stroma, and absent duct or gland formation. Strong immunohistochemical staining for S100 and epithelial membrane antigen (EMA) has been described, while cytokeratin expression has been uncommon. The majority of CSMs harbor a rearrangement involving the EWSR1 gene. Although various fusion partner genes have been discovered in ME tumors at other anatomic sites, none has yet been described in CSM. We present a case of CSM represented clinically by a papule on the mid‐upper back of a healthy 44‐year‐old female. It exhibited morphological and immunohistochemical features of a CSM with strong, diffuse S100 and alpha‐actin expression, and focal positivity for EMA and cytokeratin AE1/AE3. Fluorescence in‐situ hybridization showed an EWSR1 gene rearrangement. Massively parallel next‐generation RNA sequencing revealed PBX3 as the fusion partner. The EWSR1‐PBX3 gene fusion has been previously identified in three cases of ME tumors of bone and soft tissue, and in a case of retroperitoneal leiomyoma. This is the first report of an EWSR1‐PBX3 fusion in CSM.     

Epithelioid sarcoma‐like (pseudomyogenic) hemangioendothelioma,clinically mimicking dermatofibroma,diagnosed by skin biopsy in a 30‐year‐old man

Epithelioid sarcoma‐like (pseudomyogenic) hemangioendothelioma (ESHE) represents a rare soft tissue and bone tumor that typically presents as nodule(s) in the distal extremities of young adults. The nodules traverse several tissue planes simultaneously and can involve the dermis, subcutis, skeletal muscle and bone. ESHE shares clinical and microscopic features with epithelioid sarcoma (ES), and, accordingly, is commonly misdiagnosed as ES. However, unlike ES, which has a poor prognosis, ESHE commonly follows an indolent course. Herein, we report a case of ESHE diagnosed by skin biopsy that clinically mimicked a dermatofibroma. We also provide clinical photographs of the lesions in various stages of development, representing information that has not been previously published, to our knowledge.     

Soft tissue amyloidoma of the extremities: report of a case and review of the literature

Amyloidoma (tumoral amyloidosis) is defined as a solitary localized tumorlike deposit of amyloid, in the absence of systemic amyloidosis. Amyloidoma is the least common presentation of tissue amyloid deposition and may be of AL-type or AA-type. It has been reported in many anatomic sites including the respiratory, genitourinary, and gastrointestinal tracts, as well as internal viscera, the central nervous system, skin, breast, and soft tissues. Amyloidoma of soft tissues is extremely rare and occurs mainly in the mediastinum and abdomen. Soft tissue amyloidoma of the extremities is even more uncommon and, when strictly defined, only 11 such cases are reported in the English language to date. Most have been of AA-type and have occurred on the leg. Some have been associated with local trauma, surgery, infection, or peripheral vascular disease, and a few patients have been diabetic. We report the case of a soft tissue amyloidoma on the leg of an 85-year-old woman. Clinically, it was a subcutaneous nodule on the left shin, of approximately 4 years duration. Traumatic fat necrosis was suspected. On excision a firm gray/tan, lobulated, soft tissue mass, measuring 2.3 cm in greatest dimension, was observed. At the microscopic level, it was seen to consist mainly of amyloid, associated with a giant cell granulomatous reaction, a patchy lymphocytic infiltrate, and focal microcalcification. The features were those of a soft tissue amyloidoma of the extremity. Persistence of congophilia after pretreatment with permanganate in this case suggested the presence of AL amyloid.