Giant cell tumor of soft tissue of the breast: Case report with H3F3A mutation analysis and review of the literature.

Giant cell tumors of soft tissue (GCT-ST) arising in the breast are extremely rare. We report a unique case of breast GCT-ST coincident with ductal carcinoma in situ (DCIS), diagnosed with histological, immunohistochemical, and H3F3A (Histone H3.3) mutation analyses. A 59-year-old woman preoperatively diagnosed with DCIS underwent total mastectomy for a cystic mass. Histology revealed a tumor composed of mononuclear cells interspersed with numerous osteoclast-like giant cells, resembling giant cell tumor of bone (GCT-B), with apocrine DCIS in proximity to the tumor. The mononuclear and giant cells were immunoreactive for CD68 and negative for cytokeratins. Granulomatous diseases, carcinomas with giant cells, and giant cell-type sarcomas were excluded by histological and immunophenotypic features. Lack of H3F3A mutation eliminated the possibility of GCT-B metastasizing to the breast. These findings were consistent with GCT-ST of the breast. To our knowledge, this is the ninth reported case of breast GCT-ST, but the first case that accompanied DCIS or involved H3F3A mutation status investigation. For correct diagnosis of this rare tumor, it is important for pathologists to raise the possibility of GCT-ST when encountering giant cell-rich breast lesions and to exclude other differential diagnoses by combining the results of histological, immunohistochemical, and genetic analyses.

Subtypes of Breast Cancer in Lao P.D.R.: A Study in a Limited-Resource Setting

Aim: The purpose of this study is to evaluate the prevalence of the immunohistochemical subtypes of breast cancer among Lao women by using immunohistochemistry (according to the St. Gallen 2017 guidelines) and to study their correlation to clinicopathological features in order to help guide better treatment plans for patients. Materials and methods: Formalin-fixed and paraffin embedded tissue blocks of 76 cases of primary invasive breast cancer were retrieved from the University of Health Sciences, Vientiane, Lao PDR, from 2013 to 2016. Patients' information and previous histological reports were reviewed. Immunohistochemistry was done using antibodies against estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2/neu) and Ki-67 (MIB-1). Results: The mean age of the patients was 49 years, and the major histologic type was invasive ductal carcinoma, NOS (90.7%). The proportion of each subtype was hormone receptor-positive and HER2-negative, 44.7%; hormone receptor-positive and HER2-positive, 3.9%; hormone receptor-negative and HER2-positive, 13.2%; and triple-negative, 38.2%. ER was positive in 40.8% of the cases, while PR was positive in 47.4%. More than half of the cases were poorly differentiated cancer (65.8%), followed by moderately differentiated (34.2%). Tumors presented with pT2 (60.5%), followed by pT3 (25.0%) and pT4 (7.9%). Conclusion: Breast cancer among Lao women is characterized by a large percentage of the triple-negative subtype that is less susceptible to hormonal treatments. The empirical treatment with tamoxifen should be reconsidered since it would be less effective to these patients. More importantly, basic pathology services should be the first requirement in Lao PDR in order to provide adequate care.

Useful Application of Immunostaining to Malignant Pleural Effusion among Lao People in Vientiane Capital, Lao PDR

Background: Pathology and laboratory medicine (PALM) services are limited in low-resource countries, such as Lao PDR. Patients with malignant pleural effusion (MPE) are not properly diagnosed and treated in these situations. The purpose of this study is to confirm the usefulness of immunocytochemistry in MPE to identify the histological type and probable primary site of cancer of MPE and to discuss its usefulness in low-resource countries, such as Laos. Methods: We retrospectively reviewed glass slides of pleural effusion sent to the Department of Pathology at the University of Health Sciences from the central hospitals for cytological screening from January 2012 to December 2016. The cytological review, cell transfer and immunocytochemical staining were performed at Tokyo Medical and Dental University. Among 81 cases of MPE from Laos, 66 cases of malignant tumors that contained enough tumor cells were included in this study, and the slides were screened with 14 primary antibodies to classify the histological type and identify the probable primary site of carcinoma. Results: Among the 66 cases, 34 cases (52%) were of female patients, and 32 cases (48%) were of male patients. The patients' ages ranged from 28 to 88 years with an average of 58 years. The immunocytochemical study identified 32 cases (49%) of primary lung adenocarcinoma, two cases (3%) of malignant mesothelioma, one case (1.5%) of breast/gynecological carcinoma, one case (1.5%) of T cell lymphoma, and one case (1.5%) of B cell lymphoma. Twenty-nine cases (43.5%) were classified as carcinoma not otherwise specified. Pulmonary small cell carcinoma/squamous cell carcinoma and metastatic colon, prostate, and liver carcinoma were not identified among the cases. Conclusions: Immunocytochemistry is a useful ancillary method in MPE diagnostics. This method could be applied in the pathological laboratories in low- or middle-resource countries, such as Laos.