Metaplastic Breast Carcinoma Presenting as Cutaneous Spindle Cell Carcinoma

Squamous cell carcinoma is one of the most common primary cutaneous carcinomas, but on rare occasion, metastatic squamous cell carcinoma from a distant site or solid organ can present as a cutaneous lesion. Most metastases to the skin present as dermal nodules or involve the dermal lymphatics, but when they are intimately associated with the epidermis, distinguishing the lesion as primary or metastatic may be extremely difficult and usually requires a clinical history or high index of suspicion. A 71‐year‐old woman presented with a history of breast carcinoma, status post radiation therapy and subsequent mastectomy. She developed multiple eruptive nodules over her mastectomy site, flank and back two years later. Histologically the lesions appeared to be arising from the surface epidermis and consisted of atypical, predominantly spindle cells, some of which streamed off of the basal layer of the epidermis. Following review of the mastectomy specimen material and performing additional immunohistochemical studies, it became clear that the origin of the carcinomas was metastatic from an underlying metaplastic breast carcinoma.     

In‐transit recurrence of Merkel cell carcinoma associated with Bowen's disease: The first reported case successfully treated by avelumab

A 65‐year‐old Japanese man presented with a dome‐shaped nodule, the base of which was contiguous with a dull brown plaque, on the left leg. After local excision of the cutaneous lesion and left inguinal lymph node dissection, several dermal and subcutaneous nodules developed successively on the left lower extremity. Hematoxylin–eosin staining of the primary cutaneous lesion demonstrated uniform neoplastic cells arranged in a trabecular pattern extending from the dermis to subcutis. Mitotic figures were abundant. Although the overlying epidermis was substantially intact, the Merkel cells had invaded the epidermis, resulting in Pautrier‐like microabscesses. The hyperplastic epidermis adjacent to the nodule consisted of abnormally growing atypical keratinocytes. The enlarged left inguinal lymph node and successive secondary nodules contained Merkel cells similar to those in the primary nodule. Immunohistochemically, most tumor cells were positive for CAM5.2, synaptophysin, chromogranin A, CD56 and vimentin. The tumor cells in the left inguinal lymph node were positive for CAM5.2, synaptophysin and cytokeratin 20 but negative for CM2B4, and less than 1% of the cells expressed programmed cell death ligand 1. The patient was treated with avelumab, which showed significant efficacy against the in‐transit recurrence. Two months later, all nodules had disappeared completely. We describe a case of in‐transit recurrence of Merkel cell carcinoma that was associated histologically with Bowen's disease and was successfully treated with avelumab. Although accumulation of additional cases is needed, avelumab therapy may be a useful treatment for in‐transit recurrence of Merkel cell carcinoma.     

CD44 expression in Merkel cell carcinoma may correlate with risk of metastasis

We retrospectively studied 25 cases of cutaneous primary, locally recurrent or metastatic Merkel cell carcinoma to see if expression of the cell surface marker CD44 correlated with metastatic potential. In 3 of 6 cases in which metastasis was documented, CD44 was found on membranes of tumor cells. Three cutaneous lesions associated with local metastasis did not express CD44. Three primary tumors expressed CD44 but had not disseminated at the time of this report; follow-up after excision of the primary lesion in these cases was less than (5 months. None of the primary or locally recurrent Merkel cell carcinomas followed longer than 6 months (14 of 19 cases) expressed CD44. We conclude that expression of CD44 in Merkel cell carcinoma may eventually be of some value in the assessment of prognosis of cutaneous Merkel cell carcinoma.     

Bowenoid epidermotropic metastatic squamous cell carcinoma

Epidermotropic metastatic squamous cell carcinoma produced full-thickness cellular atypia of bowenoid carcinoma in situ or vulvar intraepithelial neoplasia, grade 3 (VIN 3), in a 73-year-old woman who had past history of uterine cervical carcinoma. The presence of intravascular tumor cell nests and areas showing smooth continuity of the malignant squamous cell nodules with the adjoining benign epidermis supported the possibility of the epidermotropic metastasis. To our knowledge, metastatic epidermotropic squamous carcinoma clinicopathologically simulating primary Bowen's disease has not been reported.     

某些皮肤转移癌的临床及病理分析

目的：为了研究皮肤转移癌的临床及病理特征。方法：选择了18例皮肤转移癌，对临床、病理进行分析。结果：皮损以红色斑块或多发结节最常见。躯干和颈部是常见的转移部位，下肢转移较少。转移灶的组织类型是腺癌(77．8％)和鳞癌(22．2％)。组织学上皮肤转移癌与原发肿瘤相同。女性最常见的原发肿瘤是乳腺癌(41．7％)，男性常见的原发肿瘤是肺癌、鼻咽癌、直肠癌、肾癌。结论：皮肤转移癌提示预后较差。     

Epidermotropic metastases from breast carcinoma showing different clinical and histopathological features on the trunk and on the scalp in a single patient

A 54-year-old female presented with the cutaneous metastases of the breast carcinoma that produced combination of pigmented zosteriform eruption on the trunk and eroded plaque on the scalp, 13 years after radical mastectomy. Histologically, zosteriform lesions displayed prominent infiltration of the epidermis in nesting or linear pattern by neoplastic cells with focal formation of intraepidermal and subepidermal vesicles due to discohesion of tumor cells and dermal edema. Examination of scalp plaque revealed ulcerations and infiltration of the epidermis with scattered basal and suprabasal malignant cells in pagetoid fashion. Immunohistochemically, tumor cells were cytokeratin 7- and estrogen receptor-positive and cytokeratin 20 negative. HMB-45 and Melan-A-stained numerous dendritic melanocytes intermingled with intraepidermal and superficial dermal tumor cells in the trunk lesion, whereas on the scalp, only occasional melanocytes surrounding intraepidermal carcinomatous cells were identified. Our case described, to our knowledge, so far unreported combination of individually rare, clinical and histological patterns of cutaneous metastases from breast carcinoma in a single patient.     

Erythematous nodules of the hand: a rare site of metastatic breast carcinoma

Acral cutaneous metastasis is a rare phenomenon. A 38-year-old woman presented with painful lesions in the left hand since 1 month. On examination, multiple painful, erythematous, lobulated plaques and nodules were present over the palmar aspect of the finger tips and thenar eminence. Biopsy of the nodule revealed lobules of small pleomorphic epithelial cells arranged in singles, small nests, cords and small abortive luminal pattern in an abundant mucoid matrix, suggestive of metastatic mucinous carcinoma. Past history revealed that the patient had undergone bilateral mastectomy for carcinoma breast. Diagnosis of cutaneous metastases is based on clinical history and histopathological examination. Identification of the primary tumor is very important for prompt treatment and prognosis. The rarity of pure acral cutaneous metastasis and its possible pathogenetic mechanisms are discussed.     

Cutaneous zosteriform squamous cell carcinoma metastasis arising in an immunocompetent patient

Cutaneous metastases from internal malignancies or primary skin cancers are uncommon, and a zosteriform pattern is very rare. Histologically, these cutaneous metastases usually appear as malignant epithelial cells located throughout the dermis or subcutaneous fat and without connection to the overlying epidermis. The presence of melanocytes in such lesions is atypical. Moreover, although zosteriform cutaneous metastases of cutaneous squamous cell carcinoma have previously been described in immunosuppressed patients, they have not been reported in immunocompetent patients. We report an unusual case of a woman with cutaneous hyperchromic zosteriform metastases, clinically mimicking a metastatic melanoma but appearing histologically as epidermotropic and pigmented metastases of a cutaneous squamous cell carcinoma.     

A peculiar form of epidermotropism in cutaneous metastatic carcinoma

A 71-year-old man developed metastatic cutaneous nodules of colon carcinoma on the scalp and chest wall. Histopathological findings revealed aggressive invasion of the tumor cells into the overlying epidermis (epidermotropic carcinoma); they occasionally adhered to the epidermal cells. These morphological features have not been described in cutaneous metastases from internal carcinomas.     

Lymphoepithelioma-like carcinoma arising in the scar from a previously excised basal cell carcinoma

We report a case of a primary lymphoepithelioma-like carcinoma of the skin (LELCS) associated with scar from a previous excision of basal cell carcinoma. The patient was a 68-year-old female with a 3.0 mm skin-colored pearly papule on her forehead that developed over 2–3 months. The patient had a history of a basal cell carcinoma in the same location, which was completely excised 1 year earlier. A biopsy and subsequent excision of the tumor were performed. The tumor consisted of small islands of large pleomorphic mitotically active epithelioid cells surrounded by a very dense lymphoplasmacytic infiltrate. The tumor was associated with dermal scar. There was no connection of tumor with the unremarkable epidermis. Immunohistochemical examination showed that the epithelioid tumor cells were positive for pan-cytokeratin and epithelial membrane antigen, supporting the morphologic impression of LELCS. The lesion was negative for Epstein-Barr virus. Retrospective review of the original excision specimen confirmed the diagnosis of an ordinary basal cell carcinoma. Forty-five cases of LELCS have been reported to date. We report the first case of LELCS to arise in the scar from an excision of a cutaneous malignancy     

Cisplatin combination chemotherapy in squamous cell carcinoma and adenoid cystic carcinoma of the skin

Seven patients with skin cancers, six with squamous cell carcinoma (SCC) and one with adenoid cystic carcinoma, were treated with cisplatin in combination with vindesine or adriamycin. Partial response was observed in three patients with squamous cell carcinomas: two cases with metastatic lung lesions and one with a primary skin lesion and lymph node metastasis. Two of the responding SCC had been resistant to previous chemotherapy, including peplomycin and mitomycin C. Multiple metastatic lesions of adenoid cystic carcinoma of the skin completely regressed after two courses of the combination chemotherapy with cisplatin and adriamycin. This report showed that cisplatin combination chemotherapy may be useful for the treatment of cutaneous squamous cell carcinoma, which is resistant to peplomycin, and adenoid cystic carcinoma of the skin.     

A rare case of primary dermal clear cell sarcoma with focal epidermotropism: An entity difficult to distinguish from melanoma

Clear cell sarcoma (CCS) is an uncommon soft-tissue sarcoma that only rarely arises within the dermis. It is challenging to distinguish dermal CCS from nodular, primary dermal, or metastatic melanoma, as they share morphologic features and immunoprofiles. We describe a dermal CCS in a 25-year-old man with a cutaneous groin mass. The lesion was initially diagnosed as melanoma, likely metastatic. On consultation, in addition to a melanoma-like tumor in the dermis, we identified focal infiltration of tumor cells into the overlying epidermis (epidermotropism), resembling primary nodular or metastatic melanoma. Given the patient's age and absence of a history of primary melanoma, fluorescence in situ hybridization (FISH) was performed, which revealed separation of the 5′ and 3′ EWSR1 probe signals on chromosome 22q12, prompting a diagnosis of CCS. Our case highlights the histopathological, immunohistochemical, and ultrastructural similarities between CCS and melanoma, and the consequent potential for major diagnostic confusion. In such cases, FISH analysis remains the key to diagnosis. CCS should be considered in patients with a melanoma-like tumor in the dermis or subcutaneous tissue without epidermal (or with minimal) involvement, or prior to diagnosing metastatic melanoma in the absence of a known history of primary melanoma, especially in young individuals.     

Cytokeratin 20: a marker for diagnosing Merkel cell carcinoma

Merkel cell carcinoma is an aggressive cutaneous neoplasm that is often difficult to diagnose because of its histologic and immunohistochemical similarity to metastatic oat cell carcinomas and other cutaneous neoplasms. Our purpose was to determine the utility of immunoperoxidase staining of cytokeratin 20 (CK 20), a newly discovered intermediate filament protein, in Merkel cell carcinomas and other cutaneous tumors. Sixty-one tumors were sectioned and stained with antibodies directed at CK 20. The staining of Merkel cell carcinomas was compared with metastatic oat cell carcinomas, lymphomas, squamous cell carcinomas, basal cell carcinomas, melanomas, metastatic carcinoids, spiradenomas, eccrine carcinomas, adenoidcystic carcinoma, sebaceous carcinomas, hidradenomas, sebaceous epitheliomas, trichoblastomas, mixed tumors, and metastatic adenocarcinomas. Nine of 10 Merkel cell carcinomas stained with antibody to CK 20. Two metastatic carcinomas to the skin were also positive. One hidradenoma and one squamous carcinoma exhibited focal staining, but were otherwise negative. All other tumors were nonstaining. Cytokeratin 20 is a sensitive and specific marker for Merkel cell carcinoma and is helpful in distinguishing between Merkel cell carcinoma and other malignant and benign neoplasms.     

Epidermotropic metastases from squamous cell carcinoma of the lower female genital tract mimicking primary Bowen's carcinoma

Epidermotropic metastases from internal malignancies are exceedingly rare. We report a striking example of epidermotropic metastatic carcinoma of the lower female genital tract to the skin of the abdomen and groin. Atypical cells were scattered throughout the epidermis, mimicking Bowen's disease. Focally, islands of atypical squamous cells were also found in the adjacent dermis. Histopathologically, the lesion resembled a primary invasive squamous cell carcinoma. However, the clinical history of a metastatic carcinoma of the genitalia and the clinical presentation with multiple lesions militated against a primary squamous cell carcinoma and favored interpretation of the lesions as epidermotropic metastases.     

Immunohistochemical techniques to compare primary vs. metastatic mucinous carcinoma of the skin

Background: Primary and metastatic mucinous carcinomas in skin are histologically indistinguishable. Immunohistochemical panels help differentiate primary and metastatic adenocarcinoma of skin, but data regarding mucinous carcinoma is scant. Methods: We stained five primary mucinous carcinomas, two mucinous carcinomas metastatic to skin and five primary breast and colon mucinous carcinomas with p63, CD15, CK5/6, CK7, CK20, calponin and D2‐40 to identify patterns that might differentiate primary from metastatic disease. We also searched for myoepithelial cells in all cases. Results: All cases of primary mucinous carcinoma of the skin were positive for CK7, 40% showed rare cells labeled for p63 and 20% of cases labeled focally for CK5/6. The breast mucinous carcinomas metastatic to the skin were negative for all markers except CK7, although 60% of primary breast carcinomas labeled for p63. Colon mucinous carcinoma labeled only for CK20. Conclusions: In a small subset of mucinous carcinomas (20% in this series), positive labeling for CK5/6 indicated primary cutaneous tumor. Staining with p63 also favored primary over metastatic disease. Myoepithelial cell layers were not consistently identified to enable the identification of primary disease. Levy G, Finkelstein A, McNiff JM. Immunohistochemical techniques to compare primary vs. metastatic mucinous carcinoma of the skin     

Myoepithelial carcinoma on the right shoulder: Case report with published work review

Myoepithelial carcinoma is a malignant tumor that can differentiate towards myoepithelial cells and commonly occur in the salivary glands. There have been only a few reports of primary cutaneous myoepithelial carcinoma; however, most cases showed subcutaneous involvement and could also be diagnosed as soft tissue myoepithelial carcinoma arising from the subcutis with dermal involvement. It may thus be impossible to distinguish a primary cutaneous from a soft tissue myoepithelial carcinoma. Herein, we describe a case of myoepithelial carcinoma on the shoulder in an 85‐year‐old Japanese woman. The tumor was located in the whole dermis and subcutis; therefore, it could be diagnosed as either a cutaneous or soft tissue myoepithelial carcinoma. We reviewed previous cases of primary cutaneous and soft tissue myoepithelial carcinomas and compared their clinical and immunohistological features. We found no obvious differences in anatomical distribution or immunohistochemical findings. However, the recurrence rate of cutaneous myoepithelial carcinomas seems to be lower than that of soft tissue carcinomas. Such a difference may be attributable to the adequate surgical margin in cutaneous carcinomas compared with the deep‐seated soft tissue carcinomas. The metastatic frequency did not significantly differ between the two types. Although we could summarize from only a small number of cases, these results indicate the difficulty in distinguishing between cutaneous and soft tissue myoepithelial carcinomas; furthermore, it may not be suitable to distinguish them on the basis of aggressive behavior.     

Superficially invasive transitional cell carcinoma of the bladder associated with distant cutaneous metastases

Cutaneous metastases from transitional cell carcinoma of the bladder are rare and most often associated with a deeply invasive primary tumor. This case report describes a 69‐year‐old male with previously resected superficially invasive primary transitional cell carcinoma of the bladder who presented with distant cutaneous and central nervous system metastases associated with recurrent bladder cancer. In addition, this case highlights the differential diagnosis of metastatic carcinomas that display a CK7/CK20 positive immunophenotype including transitional cell carcinoma, pancreatic carcinoma, cholangiocarcinoma and rare gastric carcinomas. Swick BL, Gordon JRS. Superficially invasive transitional cell carcinoma of the bladder associated with distant cutaneous metastases.     

A case of skin metastasis of lung carcinoma associated with superior vena cava syndrome

An unusual case of lung carcinoma with both skin metastasis and superior vena cava syndrome (SVCS) is reported. The histological type of the primary lesion as taken by punch biopsy was small cell carcinoma consisting of relatively small cells with hyperchromatic nuclei and scanty cytoplasm. The cutaneous metastatic lesion consisted of large cells with light-staining nuclei and small cells with deep-staining nuclei; it had foci of glandular elements by light microscopy. Neurosecretory granules characteristic of small cell carcinoma were found in the tumor cell cytoplasm by electron microscopy. Cutaneous metastatic rates, complication rates of SVCS, and histological varieties of small cell lung carcinomas are discussed.     

Intraepidermal Merkel cell carcinoma with no dermal involvement

Cutaneous Merkel cell carcinoma (MCC) typically involves the dermis. Less than 10% of MCC have epidermal involvement. Only one MCC confined exclusively to the epidermis has been previously reported but was not recognized until the lesion recurred with typical MCC in the dermis. We present a case of a wholly intraepidermal pagetoid MCC without dermal involvement in a 74-year-old man with a 2.0-cm solitary verrucous papule on the left index finger. The initial biopsy and complete excision specimens showed marked epidermal hyperplasia, focal prominent squamous cell atypia, and MCC with florid pagetoid spread through the epidermis. There was no evidence of tumor within the dermis. The pagetoid MCC tumor cells showed diffuse cytoplasmic staining with antibodies to cytokeratin 20, and negative staining for chromogranin, neurofilament, S-100, vimentin, HMB45, leukocyte common antigen, and CD3. The cell of origin of MCC is still debated. The existence of an entirely intraepidermal variant of MCC would lend support to the view that MCC is a neoplastic expression of Merkel cells in at least some cases. Dermal-based MCC is a high-grade primary cutaneous neoplasm, but MCC confined exclusively to the epidermis may have a better prognosis.