**4.3 Seromucinous hamartoma**

Seromucinous hamartoma is another subtype of hamartoma, recently described. It is a benign lesion of the sinonasal tract as well, located in the posterior nasal cavity or rhinopharynx frequently associated to REAHs. Since its description in 1974 [12], only a small number of additional cases have been reported.

The lesion occurs equally in men and women. Patients are middle-aged to elderly (mean age 50–60) and have complaints with nasal obstruction or nosebleeds. Surgical excision is the treatment of choice. It is included in the differential diagnosis of low grade epithelial proliferations of the sinonasal tract. The differentiation with low-grade non-intestinal adenocarcinoma can be tricky.

Histologically, the mass looks like a benign lesion. Lobular or haphazard proliferations of small to large glands and ducts lined by a single layer of cuboidal or flattened epithelial cells are visualized. Eosinophilic secretions are often present within tubules. The surrounding stroma often contains a lymphoplasmocytic inflammatory infiltrate. Periglandular hyalinization can be observed. There are no features suggesting a malignancy. There are no nuclear atypia.

Seromucinous hamartomas are positive for CK7 and CK19 and negative for CK14 and CK20. The serous glands are usually S100 positive and negative for p63 and muscle-specific antigen.

### **4.4 Low-grade sinonasal adenocarcinoma (LGSNAC)**

Sinonasal adenocarcinoma is the third differential diagnosis for REAH. It accounts for approximately 20% of all sinonasal malignancies and is classified into intestinal and non-intestinal salivary and non-salivary types. Intestinal adenocarcinomas (also called ITAC) take their origin in the olfactory cleftl and then extend into the ethmoid sinus, the orbit, or the anterior cranial fossa. It is an occupational disease; they typically occur in woodworkers. They look like an irregular exophytic pink necrotic and friable mass bulging into the nasal cavity located between the nasal septum and the turbinate lamella.

*REAHs and REAH-Like Lesions: Underdiagnosed lesions Often Misconfused with Nasal Polyps DOI: http://dx.doi.org/10.5772/intechopen.90327*

On microscopy, papillary and colonic types are the most common architectures. Differentiating ITAC from REAH is usually not difficult as the cell types, highgrade features, and increased mitotic index are characteristics for ITAC. ITAC is positive for CK20 and MIB1 and negative for CK7 (**Figure 14**).

**Figure 14.** *Intestinal-type adenocarcinoma: Immunohistochemistry—Positivity for CK20, CK7, and MIB1.*

**Figure 15.** *LGSNAC: Glandular proliferations lined by cuboidal to columnar cells which are usually monomorphic and cytologically bland.*

**4.3 Seromucinous hamartoma**

*Immunohistochemistry: high power/positivity of CK7.*

*Sino-Nasal and Olfactory System Disorders*

**Figure 13.**

and muscle-specific antigen.

nasal septum and the turbinate lamella.

**60**

Seromucinous hamartoma is another subtype of hamartoma, recently described. It is a benign lesion of the sinonasal tract as well, located in the posterior nasal cavity or rhinopharynx frequently associated to REAHs. Since its description in 1974 [12],

The lesion occurs equally in men and women. Patients are middle-aged to elderly (mean age 50–60) and have complaints with nasal obstruction or nosebleeds. Surgical excision is the treatment of choice. It is included in the differential diagnosis of low grade epithelial proliferations of the sinonasal tract. The differen-

Histologically, the mass looks like a benign lesion. Lobular or haphazard proliferations of small to large glands and ducts lined by a single layer of cuboidal or flattened epithelial cells are visualized. Eosinophilic secretions are often present within tubules. The surrounding stroma often contains a lymphoplasmocytic inflammatory infiltrate. Periglandular hyalinization can be observed. There are no

Seromucinous hamartomas are positive for CK7 and CK19 and negative for CK14 and CK20. The serous glands are usually S100 positive and negative for p63

Sinonasal adenocarcinoma is the third differential diagnosis for REAH. It accounts for approximately 20% of all sinonasal malignancies and is classified into intestinal and non-intestinal salivary and non-salivary types. Intestinal adenocarcinomas (also called ITAC) take their origin in the olfactory cleftl and then extend into the ethmoid sinus, the orbit, or the anterior cranial fossa. It is an occupational disease; they typically occur in woodworkers. They look like an irregular exophytic pink necrotic and friable mass bulging into the nasal cavity located between the

only a small number of additional cases have been reported.

tiation with low-grade non-intestinal adenocarcinoma can be tricky.

features suggesting a malignancy. There are no nuclear atypia.

**4.4 Low-grade sinonasal adenocarcinoma (LGSNAC)**

On the other hand, low-grade non-intestinal adenocarcinomas (LGSNAC) are less common and less invasive. There is no sex or racial predilection. There is no association with wood dust exposure. They have no tendency to give systemic metastasis. However, they have a potential for local invasion and destruction of tissue. Extensive surgery is recommended to be associated with radiotherapy in some cases.

REAHS originated from the olfactory cleft in six patients and from the anterior

*REAHs and REAH-Like Lesions: Underdiagnosed lesions Often Misconfused with Nasal Polyps*

On nasal endoscopy the lesion looked fleshy, with no vascular component and

The MRI performed in three cases was not so helpful. There were no pathognomonic features whatever was the localization. In the literature, REAHs appear as a homogeneous mass with post-contrast enhancement on T1-weighted sequences as

A biopsy was performed under local anesthesia in asymptomatic cases to make a formal diagnosis. For the other the diagnosis was made on the surgical specimen. There was no clear etiologic factor that could have played a role in the development of REAH except in one patient suffering from allergic rhinitis. There was no

Concerning the management, in two patients a wait and see attitude was proposed as the patient was not symptomatic. For the others an endoscopic resection of the lesion was performed under general anesthesia. The dissection was done in a subperiosteal plane. We have never drilled out the site of implantation. There was

The diagnosis of REAH was confirmed in all the cases by the pathologist. In one case it was a COREAH, and in another case it was a seromucinous hamartoma. These two hamartomas were located in the posterior nasal fossa.

On imaging the lesion was solitary in the olfactory cleft. No chronic

well as hyperintensity on T2-weighted images (**Figure 17**) [13].

concomitant chronic sinusitis, asthma, or aspirin intolerance.

wall of the sphenoid sinus in two cases.

*DOI: http://dx.doi.org/10.5772/intechopen.90327*

rhinosinusitis was present (**Figure 16**).

no need to do a full house ethmoidectomy.

no necrosis.

**Figure 16.**

**63**

*Comparison between CT scan and nasal endoscopy.*

Histologically, the mass originates from the surface epithelium and the seromucinous glands of the submucosa. It consists of glandular proliferations lined by cuboidal to columnar cells which are usually monomorphic and cytologically bland. It forms a diverse group of bland tubular and/or papillary tumors. Mitoses are rare. Necrosis, perineural invasion, and lymphovascular invasion are absent. The stroma contains an inflammatory infiltrate as in REAHs.

Immunohistochemistry shows the positivity for CK7 and S100 and negativity for CK20 and CDX2.

The main differential diagnosis is between LGSNAC and seromucinous hamartoma (**Figure 15**).
