Mast cell neoplasm: a challenging pathological diagnosis.

Systemic mastocytosis (SM) is a myeloid neoplasm characterized by abnormal growth and accumulation of neoplastic mast cells in at least one extracutaneous site. Clinical presentation and course are variable, most patients are developing an indolent disease and some, an aggressive/leukemic form. Because of its rarity, most physicians are unfamiliar with this disease and do not readily diagnose it. In the present retrospective study, the authors describe 12 patients diagnosed with mast cell neoplasm. Cases were selected from three institutions from Campinas and São Paulo City, Brazil. Morphological features and diagnostic pitfalls are emphasized. Patients' age ranged from 15 to 81 years (mean 51.6 years). Male and female were affected similarly (1:1). Ten patients were classified as aggressive SM, one patient as SM with an associated acute promyelocytic leukemia with t(15;17), and one patient with mast cell sarcoma. The most common clinical findings included anemia (9 patients), thrombocytopenia (3 patients), and skin lesions (3 patients). Bone marrow was involved in 11 patients at diagnosis, followed by skin (5 patients). Five morphological patterns were present: mast cell aggregates (5), plasmacytoid (4), monocytoid (2), spindle cell (2), and epithelioid/pleomorphic (1); two patients showed two histological patterns. In all cases, neoplastic cells were positive for CD117/C-KIT. C-KIT D816V mutation was present in four patients, C-KIT K509I in two, and del(7q22) in one; in five cases no mutational status was available. Despite limited resources, basically morphology and a restricted immunohistochemical panel, it is possible to diagnose mast cell neoplasm. Of note, the pathologist should recognize the different morphological variants of the disease and include adequate markers when requesting immunohistochemical studies.

Core biopsy no diagnóstico das lesões mamárias impalpáveis na categoria mamográfica BI-RADS® 5 / Core biopsy in nonpalpable BI-RADS® 5 breast lesions

INTRODUÇÃO E OBJETIVOS: Determinar a associação entre alterações mamográficas classificadas na categoria BI-RADS® 5 (lesões altamente suspeitas de malignidade) e diagnóstico histopatológico em material obtido por core biopsy estereotáxica e estabelecer o valor preditivo positivo dessa categoria mamográfica para o diagnóstico de câncer. MÉTODOS: Por meio de estudo retrospectivo, transversal, analítico, de comparação entre métodos diagnósticos, foram analisadas 70 core biopsies de lesões mamárias impalpáveis, classificadas como BI-RADS® 5, de 70 pacientes, atendidas em serviços privados de Anatomia Patológica e Radiologia em Recife, Brasil, entre 2001 e 2006. RESULTADOS: Foram mais acometidos: sexo feminino (97,1 por cento), mama esquerda (60 por cento) e quadrante superior externo (62,9 por cento). Os nódulos irregulares espiculados constituíram 70 por cento da amostra e as microcalcificações estavam presentes em 44,3 por cento. O número médio de fragmentos obtidos foi 6 ± 2. Os diagnósticos histopatológicos foram: carcinoma (59 casos; 84,3 por cento); lesões benignas (sete casos; 10 por cento) e hiperplasia ductal atípica ou lesão suspeita de malignidade (quatro casos; 5,7 por cento). Os nódulos irregulares espiculados corresponderam significantemente a carcinoma invasivo (p = 0,005). O carcinoma ductal in situ (CDIS) padrão comedônico puro associou-se mais frequentemente às microcalcificações na histologia. Os valores preditivos positivos foram: 84,3 por cento para a categoria mamográfica BI-RADS® 5 como um todo; 100 por cento para nódulo irregular espiculado com microcalcificações; 87,8 por cento para nódulo irregular espiculado com ou sem microcalcificações; 84,2 por cento para nódulo irregular espiculado sem microcalcificações; e 75 por cento para microcalcificações sem nódulos. CONCLUSÃO: Lesões mamárias impalpáveis da categoria mamográfica BI-RADS® 5 são de alto valor preditivo para carcinoma, particularmente os nódulos irregulares ...

INTRODUCTION AND OBJECTIVES: To determine the association between mammographic alterations classified as BI-RADS® 5 category (lesions highly suggestive of malignancy) and the corresponding histopathological diagnoses of samples obtained by stereotactic core biopsy; to establish the positive predictive value of this mammographic category for the diagnosis of cancer. METHODS: By means of retrospective cross sectional analytical study comparing diagnostic methods, we investigated seventy stereotactic core biopsies of nonpalpable breast lesions classified as BI-RADS® 5 from 70 patients seen at private Anatomic Pathology and Radiology services in Recife (Pernambuco state, Brazil) from 2001 to 2006. RESULTS: Female patients (97.1 percent) were predominantly affected. The left breast (60 percent) and upper outer quadrant (62.9 percent) were more commonly involved. Irregular spiculated nodules corresponded to 70 percent of the cases, and microcalcifications to 44.3 percent. The mean number of core fragments was 6 ± 2. The histopathological diagnoses were: carcinoma (59 cases; 84.3 percent), benign lesions (seven cases; 10 percent) and atypical ductal hyperplasia or lesion suspected of malignancy (four cases; 5.7 percent). Invasive carcinoma was significantly associated with irregular spiculated nodules (p = 0.005). Pure comedo DCIS was more frequently associated with microcalcifications on histology. The positive predictive values were: 84.3 percent for BI-RADS® 5 category as a whole, 100 percent for irregular spiculated nodules with microcalcifications, 87.8 percent for irregular spiculated nodules with or without calcifications, 84.2 percent for irregular spiculated nodules without microcalcifications and 75 percent for microcalcifications without nodes. CONCLUSION: Breast lesions classified as BI-RADS® 5 have a high positive predictive value for carcinoma, particularly irregular spiculated nodules with microcalcifications.