Sarcomas of the posterior mediastinum are rare and correspond mostly to neurogenic tumors. We studied 18 cases of liposarcoma presenting in the posterior mediastinum; because of their unusual location, some of these tumors posed difficulties for diagnosis. There were 11 men and 7 women aged 29-87 years (mean: 57). The tumors were large lobulated masses ranging from 6 to 30 cm in greatest diameter (median: 15 cm). Symptoms included cough, dysphagia, and chest pain. Four patients were asymptomatic and the tumors were discovered incidentally on chest X-rays. Histologically, 10/18 (55%) cases were atypical lipomatous tumor/ well-differentiated liposarcoma, one of which harbored a smooth muscle component (lipoleiomyosarcoma); 3/18 (16%) were de-differentiated liposarcoma, one of which also harbored a smooth muscle component; 3/18 (16%) were myxoid/round cell liposarcoma; and 2/18 (11%) were pleomorphic liposarcoma. The cases of well-differentiated liposarcoma were mostly of the sclerosing type; however, five of them also showed prominent myxoid stroma closely resembling myxoid liposarcoma. Immunohistochemistry was performed in selected cases; 4/8 cases tested showed focal positivity for S-100 protein and 5/8 cases showed nuclear positivity for MDM-2. The three cases of myxoid liposarcoma were all negative for MDM2. Both cases of lipoleiomyosarcoma showed positivity for SMA and desmin in the smooth muscle component. FISH was performed in two cases of well-differentiated liposarcoma and high levels of amplification of MDM2 at 12q13-15 were observed; the CHOP translocation at 12q13.1-q13.2 was absent in both cases. Complete surgical excision was performed in 11 cases; however, negative surgical margins were achieved only in four. Clinical follow-up ranging from 1 to 192 months (median 28 months) was available for 13 patients. Two patients with myxoid/round cell liposarcoma died of tumor after 4 months and 3 years, respectively. Both had widely disseminated metastatic disease at the time of death. Six patients (6/10) with well-differentiated liposarcoma were alive and well with no evidence of disease (at 4, 7, 12, 15, and 25 months) and three (3/10) were alive with disease (at 3, 4, and 6 months). One patient with well-differentiated liposarcoma had multiple recurrences and a liver metastasis after 14 years; however, the patient was alive and well at 16 years. Five patients were lost to follow-up. In general, the biologic behavior of liposarcomas in the posterior mediastinum seems to correlate well with the histologic subtype and mirrors that of their counterpart in the retroperitoneum.

These findings suggest that DLBCLs with HL features constitute a distinctive subgroup of aggressive lymphomas whose neoplastic growth and peculiar characteristics could be facilitated by a particular microenvironment found in the mediastinum.

The distinction of metastatic carcinomas to the skin from poorly differentiated primary cutaneous carcinomas and sometimes primary benign adnexal tumors can pose a significant diagnostic challenge. The purpose of this study was to evaluate the role of p63 and podoplanin (D2-40) immunoreactivity for separating primary skin tumors vs. cutaneous metastases of carcinomas from internal organs. Thirty seven primary tumors and 42 cutaneous metastatic adenocarcinomas were evaluated. The 37 primary cutaneous tumors included 14 cases of benign adnexal tumors, 9 malignant skin adnexal neoplasms, and 14 primary squamous and basal cell carcinomas. The 42 metastatic adenocarcinomas all corresponded to metastases from patients with a well-documented history of a primary tumor at another location. We found variable positivity with podoplanin in all primary cutaneous neoplasms including spiradenoma (6/6), hidradenoma (2/4), cylindroma (3/3), desmoplastic trichilemmoma (1/1), poorly differentiated squamous cell carcinoma (4/4), sebaceous carcinoma (1/1), basal cell carcinoma (4/10), trichilemmal carcinoma (2/2), eccrine carcinoma (3/3), microcystic adnexal carcinoma (1/1), adnexal carcinoma NOS (1/1), and porocarcinoma (1/1). In contrast, all metastatic carcinomas were negative (0/42) for podoplanin. In regards to p63, all cases of primary cutaneous tumors were positive for p63 (37/37); in contrast, all cutaneous metastatic carcinomas were negative (0/42). Sensitivity, specificity, and positive and negative predictive values of podoplanin and p63 immunoreactivity to separate primary skin neoplasms from metastatic carcinomas were 78.4, 100.0, 100.0 and 84.0% for podoplanin, respectively, and 100.0, 100.0, 100.0 and 100.0% for p63, respectively. The differences in p63 and podoplanin immunohistochemical expression between primary skin tumors and metastatic carcinomas to the skin were statistically significant (p < 0, 0001). The results of our study suggest that the combined expression of p63 and podoplanin are a useful adjunct for the diagnosis of skin tumors in the clinical setting of a questionable metastasis and may be relatively specific for distinguishing primary skin tumors from metastatic carcinomas to the skin.

Primary cutaneous anaplastic large T-cell lymphoma (PCALCL) is a well-defined CD30-positive lymphoproliferative disorder with relatively good prognosis and response to treatment. We describe a case of PCALCL expressing CD8. The patient is a 57-year-old man that clinically presented with an ulcerated nodule in his left middle finger. Histopathologic sections showed an ulcerated epidermis with a diffuse lymphocytic infiltrate in the superficial dermis with focal epidermotropism. The large cohesive atypical cells were admixed with a reactive infiltrate composed of neutrophils, eosinophils, and small lymphocytes. Immunohistochemical studies showed the tumor cells to be strongly positive for CD8, CD30, and TIA-1, focally positive for CD3, and negative for CD4, CD20, CD56, Anaplastic Lymphoma Kinase (ALK-1), and HSV. Epstein-Barr virus by in situ hybridization was negative. The diagnosis of a CD8+ PCALCL was confirmed. There is limited precedent literature regarding CD8-positive PCALCL and this case falls within the clinical and histopathologic spectrum of CD30+ lymphoproliferative disorders. CD8/CD30 coexpression is rare in PCALCL and may have important clinical and prognostic implications. To the best of our knowledge there are only 4 previously reported cases describing similar findings.