Nasal seromucinous hamartoma (microglandular adenosis of the nose): a morphological and molecular study of five cases

Abstract

Five cases of nasal seromucinous hamartoma were studied and their clinical, morphological, immunohistochemical and molecular data are reported. The patients, three females and two males, ranged in age from 49 to 66 years (mean 56 year, SD ± 7.91). All lesions were located in the nasal cavity. In four cases where follow-up was obtained, no recurrence was evident. In all cases, numerous small seromucinous tubules, embedded in a cellular stroma, were present in the lamina propria. Tubules were lined by one layer of cuboidal cells which displayed luminal phenotype positive for lysozyme and EMA in four, and S100 protein in all cases. Collagen IV and laminin positive basal lamina outlined the tubules which lacked basal cells. Stromal spindle cells present among tubules were immunoreactive for calponin in all cases and for alpha-smooth muscle actin in four cases. DNA mutation analysis of mitochondrial D-loop region was performed by direct sequencing in order to verify the mutation rate of these lesions. The tubules of the five seromucinous hamartomas showed a higher mutation rate especially in heteroplasmy (0.52% homoplasmy, 2.02% heteroplasmy) in comparison to normal seromucinous glands which exhibited a lower mutation frequency (0.83%). This is considered a sign of a low cellular proliferation rate consistent with a benign process. It is concluded that nasal seromucinous hamartomas are benign glandular proliferations that may resemble microglandular adenosis of the breast. Their distinction from benign and malignant mimics is discussed.

Sinonasal Seromucinous Hamartoma: A Review of the Literature and a Case Report with Focal Myoepithelial Cells

“…They are both associated with inflammation. In addition, foci of seromucinous hamartoma are frequently found in REAH, and vice versa [5,6,8,9]. Our case also demonstrates focal REAH-like features, and supports the suggestion that REAH and seromucinous hamartoma are related lesions.…”

“…However, in contrast to seromucinous hamartoma, LGSNAC typically has complex growth patterns including micropapillary architecture, and glands which are back-to-back or fused. Immunohistochemistry is not helpful in separating seromucinous hamartoma and LGSNAC, as both are negative for CK20 and positive for CK7, CK19 and S100 [5,6,10]. In both entities p63 is usually negative.…”

“…Ambrosini-Spaltro et al [6] extracted mitochondrial DNA (mtDNA) from normal tissue and from the proliferating tubules of five cases of seromucinous hamartoma. Using polymerase chain reaction (PCR) they analyzed the mitochondrial D-loop sequences, and determined that compared to normal tissue, the seromucinous hamartomas had a higher mean mtDNA mutation rate, especially in heteroplasmy (a mixture of wild type and mutant DNA).…”

“…The entity was initially described by Baillie and Batsakis in 1974 [1] as a single case report. Since then, 20 additional cases have been reported in the English literature [2][3][4][5][6][7][8] (Table 1). The male to female ratio is approximately 1:1.…”

“…Architectural features of malignancy such as back-to-back glands, cribriform patterns, and invasion are not seen. Two recently published case series [5,6] have determined that seromucinous hamartomas are positive for CK7 and CK19, and negative for CK14 and CK20. The serous glands are usually S100 positive (at least focally), and are negative for p63 and muscle-specific antigen.…”