A case of pulmonary hamartoma with distinctive histopathological features: A discussion of its differential diagnosis and histogenesis

Abstract

We herein describe a case of a benign pulmonary tumor with distinctive histopathological features. A 55-year-old Japanese male presented with a well-demarcated tumor in the left upper lobe of his lung, which gradually increased in size from 18 to 21 mm over 24 months. The resected tumor consisted of an epithelial component of compact irregular glands and mesenchymal component of fascicles between the glands. The differentiation of pneumocytes and smooth muscle cells was immunohistochemically detected in the epithelial component and the mesenchymal component, respectively. No mitosis, necrosis, bleeding, or invasion was observed. A histopathologic diagnosis of fibroleiomyomatous hamartoma was made. We also review previously reported tumors with similar histopathological features and discuss their differential diagnosis and histogenesis.

An unusual case of pulmonary hamartoma with predominant bronchial mucous glands in the peripheral lung

“…A major study of PH showed that 86.9% of PH comprised epithelial components . Although no reports have described the proportion of epithelial components in detail, a few cases of PH show prominent epithelial entrapments . This rare variant of PH, which is composed of smooth muscle fascicles and tubular or cleft‐like entrapped epithelial components without other mesenchymal components, has been described using different diagnostic terms, including fibroleiomyomatous hamartoma, hamartoma, adenomyomatous hamartoma, or adenofibroma .…”

“…1 Although no reports have described the proportion of epithelial components in detail, a few cases of PH show prominent epithelial entrapments. 9,10 This rare variant of PH, which is composed of smooth muscle fascicles and tubular or cleft-like entrapped epithelial components without other mesenchymal components, has been described using different diagnostic terms, including fibroleiomyomatous hamartoma, hamartoma, adenomyomatous hamartoma, or adenofibroma. 9,10 To the best of our knowledge, PH with predominant bronchial mucous glands has not been reported to date and this is the first such case report.…”

Unusual cystic hamartomatous lung lesion with clinical manifestation of subpleural bullae in a woman of reproductive age: A case report

“…However, this case could not be classified as a chondroid hamartoma, which shows solid nodules and a variable amount of cartilage. Rare histological subtypes of pulmonary hamartoma showing leiomyomatous growth patterns, which are called leiomyomatous or fibroleiomyomatous hamartomas, also exhibit solid nodules. Two cases of pulmonary hamartoma with multilocular morphology similar to the present case were reported to show intrapulmonary masses without clinical manifestation of subpleural bullae, and the smooth muscle layers in one of these cases showed no expression of sex steroid hormone receptors.…”

“…Interestingly, chondroid hamartomas contain stromal cells immunohistochemically expressing ER, PgR, and smooth muscle markers; however, the stromal cells differed from the spindle cells of the present case in that the stromal cells were associated with fibromyxoid substances and were also positive for S100 and glial fibrillary acid protein. Among other rare cases of pulmonary hamartoma, a recent case report described a fibroleiomyomatous hamartoma containing smooth muscle marker‐positive spindle cells that were also positive for PgR but not ER. Additionally, another case of fibroleiomyomatous hamartoma contained stromal cells that were negative for both receptors.…”

A rare pulmonary hamartoma: fibroleiomyomatous hamartoma

“…Pulmonary fibroleiomyomatous hamartoma was first described as “diffuse fibroleiomyomatous hamartomatosis” by Cruickshank et al in 1953 [ 1 ]. To date, only five cases of solitary pulmonary fibroleiomyomatous hamartoma have been reported [ 2 , 3 ]. These tumors represent an important group of benign pulmonary tumors which classically present as incidental “coin lesions” and which must be differentiated from primary and metastatic malignant neoplasms.…”